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 A275377 Number of odd prime factors (with multiplicity) of generalized Fermat number 3^(2^n) + 1. 4
 0, 1, 1, 2, 1, 1, 1, 5, 4, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Arkadiusz Wesolowski, A 93-digit prime factor of b(9) FORMULA a(n) = A001222(A059919(n)) - 1 for n > 0. - Felix Fröhlich, Jul 25 2016 EXAMPLE b(n) = (3^(2^n) + 1)/2. Complete Factorizations b(0) = 2 b(1) = 5 b(2) = 41 b(3) = 17*193 b(4) = 21523361 b(5) = 926510094425921 b(6) = 1716841910146256242328924544641 b(7) = 257*275201*138424618868737*3913786281514524929*P21 b(8) = 12289*8972801*891206124520373602817*P90 b(9) = 134382593*22320686081*12079910333441*100512627347897906177*P93*P101 PROG (PARI) a001222(n) = bigomega(n) a059919(n) = 3^(2^n)+1 a(n) = if(n==0, 0, a001222(a059919(n))-1) \\ Felix Fröhlich, Jul 25 2016 CROSSREFS Cf. A059919, A273945. Sequence in context: A227578 A181783 A121395 * A219585 A292464 A090628 Adjacent sequences:  A275374 A275375 A275376 * A275378 A275379 A275380 KEYWORD nonn,hard,more AUTHOR Arkadiusz Wesolowski, Jul 25 2016 EXTENSIONS a(9) was found in 2008 by Tom Womack STATUS approved

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Last modified June 16 12:38 EDT 2021. Contains 345057 sequences. (Running on oeis4.)