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A275382 Number of odd prime factors (with multiplicity) of generalized Fermat number 11^(2^n) + 1. 2
1, 1, 1, 2, 2, 3, 2, 5, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

FORMULA

a(n) = A001222(A199592(n)) - 1 for n > 0. - Felix Fröhlich, Jul 25 2016

EXAMPLE

b(n) = (11^(2^n) + 1)/2.

Complete Factorizations

b(0) = 2*3

b(1) = 61

b(2) = 7321

b(3) = 17*6304673

b(4) = 51329*447600088289

b(5) = 193*257*21283620033217629539178799361

b(6) = 316955440822738177*P49

b(7) = 15361*111489577217*574341646346402207998363393*

       4018529583345312964042058778793458689*P55

b(8) = 15190529*4696846849*19618834249745000485889*

       4393553986026616439660661873903822389581313*

       290103547098489711747952055517085778590240759297*P138

PROG

(PARI) a001222(n) = bigomega(n)

a199592(n) = 11^(2^n)+1

a(n) = if(n==0, 1, a001222(a199592(n))-1) \\ Felix Fröhlich, Jul 25 2016

CROSSREFS

Cf. A199592, A273949.

Sequence in context: A050323 A318286 A214646 * A199583 A157922 A015995

Adjacent sequences:  A275379 A275380 A275381 * A275383 A275384 A275385

KEYWORD

nonn,hard,more

AUTHOR

Arkadiusz Wesolowski, Jul 25 2016

EXTENSIONS

a(8) was found in 2006 by Bruce Dodson

STATUS

approved

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Last modified January 18 13:47 EST 2020. Contains 331009 sequences. (Running on oeis4.)