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A367008
Number of prime factors of n*2^n + 1, counted with multiplicity.
2
0, 1, 2, 2, 2, 2, 3, 3, 2, 2, 4, 2, 3, 3, 3, 3, 2, 4, 4, 4, 5, 2, 4, 4, 4, 4, 5, 4, 3, 3, 6, 6, 3, 2, 5, 2, 4, 3, 4, 3, 3, 4, 4, 5, 4, 4, 5, 5, 4, 5, 6, 3, 6, 3, 5, 4, 4, 5, 5, 4, 4, 7, 3, 3, 7, 5, 9, 5, 4, 5, 5, 6, 5, 5, 5, 5, 5, 4, 4, 6, 4, 4, 4, 5, 4, 7, 6
OFFSET
0,3
COMMENTS
The numbers n*2^n+1 are called Cullen numbers.
LINKS
FORMULA
a(n) = bigomega(n*2^n + 1) = A001222(A002064(n)).
MATHEMATICA
Table[PrimeOmega[n*2^n + 1], {n, 0, 100}] (* Amiram Eldar, Jan 06 2024 *)
PROG
(PARI) a(n) = bigomega(n*2^n + 1); \\ Amiram Eldar, Jan 06 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 31 2023
STATUS
approved