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Revision History for A325251 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

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Numbers whose omega-sequence covers an initial interval of positive integers.
(history; published version)
#8 by R. J. Mathar at Thu Aug 22 09:53:36 EDT 2019
STATUS

editing

approved

#7 by R. J. Mathar at Thu Aug 22 09:53:32 EDT 2019
STATUS

approved

editing

#6 by Susanna Cuyler at Wed Apr 17 19:08:31 EDT 2019
STATUS

proposed

approved

#5 by Gus Wiseman at Wed Apr 17 09:58:59 EDT 2019
STATUS

editing

proposed

#4 by Gus Wiseman at Wed Apr 17 09:57:01 EDT 2019
#3 by Gus Wiseman at Wed Apr 17 09:56:01 EDT 2019
MATHEMATICA

omseq[n_Integer]:=If[n<=1, {}, Total/@NestWhileList[Sort[Length/@Split[#1]]&, Sort[Last/@FactorInteger[n]], Total[#]>1&]];

CROSSREFS

Omega-sequence statistics: A001222 (first omega), A001221 (second), A001222 (first omega), A071625 (third omega), A323022 (fourth omega), A304465 (second-to-last omega), A182850 or A323014 (length), A323022 (fourth/frequency depth), A323023 A325248 (allHeinz number).

#2 by Gus Wiseman at Tue Apr 16 17:49:10 EDT 2019
NAME

allocated for Gus WisemanNumbers whose omega-sequence covers an initial interval of positive integers.

DATA

1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 25, 26, 28, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 57, 58, 59, 60, 61, 62, 63, 65, 67, 68, 69, 71, 73, 74, 75, 76, 77, 79, 82, 83, 84, 85, 86

OFFSET

1,2

COMMENTS

We define the omega-sequence of n (row n of A323023) to have length A323014(n) = adjusted frequency depth of n, and the k-th term is Omega(red^{k-1}(n)), where Omega = A001222 and red^{k} is the k-th functional iteration of red = A181819, defined by red(n = p^i*...*q^j) = prime(i)*...*prime(j) = product of primes indexed by the prime exponents of n. For example, we have 180 -> 18 -> 6 -> 4 -> 3, so the omega-sequence of 180 is (5,3,2,2,1).

The enumeration of these partitions by sum is given by A325260.

EXAMPLE

The sequence of terms together with their omega sequences begins:

1: 31: 1 63: 3 2 2 1

2: 1 33: 2 2 1 65: 2 2 1

3: 1 34: 2 2 1 67: 1

4: 2 1 35: 2 2 1 68: 3 2 2 1

5: 1 37: 1 69: 2 2 1

6: 2 2 1 38: 2 2 1 71: 1

7: 1 39: 2 2 1 73: 1

9: 2 1 41: 1 74: 2 2 1

10: 2 2 1 43: 1 75: 3 2 2 1

11: 1 44: 3 2 2 1 76: 3 2 2 1

12: 3 2 2 1 45: 3 2 2 1 77: 2 2 1

13: 1 46: 2 2 1 79: 1

14: 2 2 1 47: 1 82: 2 2 1

15: 2 2 1 49: 2 1 83: 1

17: 1 50: 3 2 2 1 84: 4 3 2 2 1

18: 3 2 2 1 51: 2 2 1 85: 2 2 1

19: 1 52: 3 2 2 1 86: 2 2 1

20: 3 2 2 1 53: 1 87: 2 2 1

21: 2 2 1 55: 2 2 1 89: 1

22: 2 2 1 57: 2 2 1 90: 4 3 2 2 1

23: 1 58: 2 2 1 91: 2 2 1

25: 2 1 59: 1 92: 3 2 2 1

26: 2 2 1 60: 4 3 2 2 1 93: 2 2 1

28: 3 2 2 1 61: 1 94: 2 2 1

29: 1 62: 2 2 1 95: 2 2 1

MATHEMATICA

normQ[m_]:=Or[m=={}, Union[m]==Range[Max[m]]];

omseq[n_Integer]:=If[n<=1, {}, Total/@NestWhileList[Sort[Length/@Split[#1]]&, Sort[Last/@FactorInteger[n]], Total[#]>1&]];

Select[Range[100], normQ[omseq[#]]&]

CROSSREFS

Positions of normal numbers (A055932) in A325248.

Cf. A000430, A055932, A056239, A112798, A181819, A325247, A325257, A325260, A325261, A325277.

Omega-sequence statistics: A001221 (second), A001222 (first), A071625 (third), A304465 (second-to-last), A323014 (length), A323022 (fourth), A323023 (all).

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Apr 16 2019

STATUS

approved

editing

#1 by Gus Wiseman at Sun Apr 14 10:31:36 EDT 2019
NAME

allocated for Gus Wiseman

KEYWORD

allocated

STATUS

approved