A366618 a(n) = phi(5^n+1), where phi is Euler's totient function (A000010).

1, 2, 12, 36, 312, 1040, 7200, 25088, 183808, 557928, 4396800, 15333120, 121680000, 406812744, 2817007200, 8558784000, 76264519680, 254230063200, 1710194342400, 6349120596480, 47334145996800, 127169887444992, 1088029470747648, 3889097389599864

Offset

0,2

Links

Max Alekseyev, Table of n, a(n) for n = 0..471

Prog

(PARI) {a(n) = eulerphi(5^n+1)}

Crossrefs

Cf. A000010, A034474, A057939, A074478, A295502, A366615, A366616, A366617.

Cf. A053285, A366579, A366608, A366630, A366639, A366658, A366667, A366669, A366690, A366716.

Sequence in context: A352281 A361570 A294464 * A330781 A185788 A305864

Adjacent sequences: A366615 A366616 A366617 * A366619 A366620 A366621

Keyword

nonn

Author

Sean A. Irvine, Oct 14 2023

Status

approved