A295496 a(n) = phi(6^n-1)/n, where phi is Euler's totient function (A000010).

4, 12, 56, 216, 1240, 5040, 31992, 139968, 828576, 3720000, 25238048, 104509440, 803499840, 3687014016, 24373440000, 110630707200, 790546192128, 3463116249600, 25522921047520, 108957312000000, 816244048599840, 3924124012353600, 26682733370563200

Offset

1,1

Links

Seiichi Manyama, Table of n, a(n) for n = 1..100

Eric Weisstein's World of Mathematics, Totient Function.

Wikipedia, Euler's totient function.

Prog

(PARI) {a(n) = eulerphi(6^n-1)/n}

Crossrefs

Column k=6 of A369291.

phi(k^n-1)/n: A011260 (k=2), A027385 (k=3), A027695 (k=4), A027741 (k=5), this sequence (k=6), A027743 (k=7), A027744 (k=8), A027745 (k=9), A295497 (k=10), A319166 (k=11).

Sequence in context: A179607 A149422 A149423 * A164575 A124004 A243785

Adjacent sequences: A295493 A295494 A295495 * A295497 A295498 A295499

Keyword

nonn

Author

Seiichi Manyama, Nov 22 2017

Status

approved