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A275383 Number of prime factors (with multiplicity) of generalized Fermat number 12^(2^n) + 1. 3
1, 2, 2, 3, 2, 2, 5, 2, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..8.

Arkadiusz Wesolowski, A 96-digit prime factor of b(8)

FORMULA

a(n) = A001222(A152585(n)). - Felix Fröhlich, Jul 25 2016

EXAMPLE

b(n) = 12^(2^n) + 1.

Complete Factorizations

b(0) = 13

b(1) = 5*29

b(2) = 89*233

b(3) = 17*97*260753

b(4) = 153953*1200913648289

b(5) = 769*44450180997616192602560262634753

b(6) = 36097*81281*69619841*73389730593973249*P35

b(7) = 257*P136

b(8) = 8253953*295278642689*5763919006323142831065059613697*P96*P132

MATHEMATICA

Table[PrimeOmega[12^(2^n) + 1], {n, 0, 7}] (* Michael De Vlieger, Jul 26 2016 *)

PROG

(PARI) a(n) = bigomega(factor(12^(2^n)+1))

CROSSREFS

Cf. A152585, A273950.

Sequence in context: A213023 A068050 A210967 * A206762 A212281 A225637

Adjacent sequences:  A275380 A275381 A275382 * A275384 A275385 A275386

KEYWORD

nonn,hard,more

AUTHOR

Arkadiusz Wesolowski, Jul 25 2016

EXTENSIONS

a(8) was found in 2009 by Tom Womack

STATUS

approved

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Last modified January 27 04:57 EST 2020. Contains 331291 sequences. (Running on oeis4.)