A328578 - OEIS

A328578

Index of the least prime not dividing A276086(A276086(n)): a(n) = A257993(A276087(n)).

2, 1, 3, 1, 4, 1, 3, 1, 4, 1, 5, 1, 2, 1, 5, 1, 4, 1, 3, 1, 6, 1, 6, 1, 2, 1, 6, 1, 7, 1, 2, 1, 4, 1, 3, 1, 3, 1, 5, 1, 6, 1, 2, 1, 6, 1, 6, 1, 3, 1, 7, 1, 7, 1, 2, 1, 7, 1, 5, 1, 2, 1, 5, 1, 4, 1, 3, 1, 6, 1, 6, 1, 2, 1, 7, 1, 7, 1, 3, 1, 7, 1, 8, 1, 2, 1, 6, 1, 8, 1, 2, 1, 6, 1, 7, 1, 3, 1, 7, 1, 7, 1, 2, 1, 7, 1

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OFFSET

0,1

COMMENTS

Index of the least significant zero digit in the primorial base expansion of A276086(n), when the rightmost digit is in the position 1.

The scatter plot shows both regular looking as well as more chaotic regions. This can be more clearly seen in related A328579. See also A328839.

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..32768

Rémy Sigrist, Colored logarithmic scatterplot of the ordinal transform of the sequence for n = 0..510510

Rémy Sigrist, Density plot of the sequence for n = 0..510510

Index entries for sequences related to primorial base

FORMULA

a(n) = A328570(A276086(n)) = A257993(A276087(n)) = A055396(A328403(n)).

a(n) = A000720(A328579(n)).

a(n) = A257993(n) + A328590(n).

a(n) = A055396(A328763(n)).

For all n >= 0, a(A328761(n)) = n.

PROG

(PARI)

A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };

A328570(n) = { my(i=1, p=2); while(n && (n%p), i++; n = n\p; p = nextprime(1+p)); (i); };

A328578(n) = A328570(A276086(n));

(PARI)

A257993(n) = { for(i=1, oo, if(n%prime(i), return(i))); }

A328578(n) = A257993(A276086(A276086(n)));

CROSSREFS

Cf. A000720, A055396, A276086, A276087, A328403, A328570, A328579 (the corresponding prime), A328590, A328763, A328766, A328839.

Cf. A328585 (where equal with A257993), A328587 (less than), A328588 (greater than).

Cf. A328761 (the first occurrence of each n).

Cf. also array A328631 and its rows A005408, A328632, A328633, A328634, A328635, A328636 (positions of terms 1 .. 6 in this sequence).

Sequence in context: A229944 A366421 A218533 * A351613 A094741 A360653

Adjacent sequences: A328575 A328576 A328577 * A328579 A328580 A328581

KEYWORD

nonn,look

AUTHOR

Antti Karttunen, Oct 20 2019

STATUS

approved