

A064136


Number of divisors of 11^n + 1 that are relatively prime to 11^m + 1 for all 0 < m < n.


7



2, 6, 2, 2, 2, 2, 4, 2, 4, 2, 2, 16, 4, 8, 8, 4, 4, 8, 2, 16, 4, 2, 4, 16, 16, 4, 2, 4, 16, 8, 2, 16, 8, 16, 16, 48, 8, 4, 4, 8, 4, 8, 4, 4, 16, 8, 16, 16, 4, 16, 8, 8, 2, 16, 16, 32, 16, 8, 16, 16, 4, 8, 4, 16, 4, 8, 4, 64, 32, 32, 4, 8, 8, 32, 64, 8, 16, 16, 64, 16, 128, 8, 8
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OFFSET

0,1


LINKS

Sean A. Irvine, Table of n, a(n) for n = 0..301
Sam Wagstaff, Cunningham Project, Factorizations of 11^n1, n<=240


MATHEMATICA

a = {1}; Do[ d = Divisors[ 11^n + 1 ]; l = Length[ d ]; c = 0; k = 1; While[ k < l + 1, If[ Union[ GCD[ a, d[ [ k ] ] ] ] == {1}, c++ ]; k++ ]; Print[ c ]; a = Union[ Flatten[ Append[ a, Transpose[ FactorInteger[ 11^n + 1 ] ][ [ 1 ] ] ] ] ], {n, 0, 55} ]


PROG

(PARI) a(n) = if (n==0, 2, sumdiv(11^n+1, d, vecsum(vector(n1, k, gcd(d, 11^k+1) == 1)) == n1)); \\ Michel Marcus, Jun 24 2018


CROSSREFS

Cf. A064131, A064132, A064133, A064134, A064135, A064137.
Sequence in context: A303335 A289382 A062539 * A171898 A320575 A110218
Adjacent sequences: A064133 A064134 A064135 * A064137 A064138 A064139


KEYWORD

nonn,more


AUTHOR

Robert G. Wilson v, Sep 10 2001


EXTENSIONS

a(1) corrected and more terms from Michel Marcus, Jul 02 2018
a(71)a(82) from Robert Price, May 26 2019


STATUS

approved



