A045767 - OEIS

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A045767

Number of prime factors of triple factorials n!!! (A007661), with multiplicity.

0, 1, 1, 2, 2, 3, 3, 5, 5, 5, 6, 8, 6, 8, 10, 10, 9, 13, 11, 12, 15, 13, 13, 19, 15, 15, 22, 18, 16, 25, 19, 21, 27, 21, 23, 31, 22, 25, 33, 26, 26, 36, 27, 29, 39, 29, 30, 44, 31, 33, 46, 34, 34, 50, 36, 38, 52, 38, 39, 56, 39, 41, 59, 45, 43, 62, 46, 46, 64, 49, 47, 69, 50, 49

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

Rest[PrimeOmega/@RecurrenceTable[{a[0]==a[1]==1, a[2]==2, a[n]==n*a[n-3]}, a, {n, 80}]] (* Harvey P. Dale, May 17 2012 *)

Table[PrimeOmega[Times@@Range[n, 1, -3]], {n, 80}] (* Harvey P. Dale, Apr 11 2020 *)

CROSSREFS

Sequence in context: A072729 A057872 A059974 * A108221 A169682 A082524

Adjacent sequences: A045764 A045765 A045766 * A045768 A045769 A045770

KEYWORD

nonn,easy

AUTHOR

Jeff Burch

STATUS

approved