A366635 a(n) = phi(7^n-1), where phi is Euler's totient function (A000010).

2, 16, 108, 640, 5600, 36288, 264992, 1536000, 12387168, 85120000, 658519752, 3135283200, 32296336800, 216063877120, 1450340640000, 8333819904000, 77537969371008, 488237947481088, 3790563394976072, 19162214400000000, 170264753751665664, 1245495178700551680

Offset

1,1

Links

Max Alekseyev, Table of n, a(n) for n = 1..388

Mathematica

EulerPhi[7^Range[30] - 1] (* Wesley Ivan Hurt, Oct 15 2023 *)

Prog

(PARI) {a(n) = eulerphi(7^n-1)}

Crossrefs

phi(k^n-1): A053287 (k=2), A295500 (k=3), A295501 (k=4), A295502 (k=5), A366623 (k=6), this sequence (k=7), A366654 (k=8), A366663 (k=9), A295503 (k=10), A366685 (k=11), A366711 (k=12).

Cf. A000010, A024075, A366632, A366633, A366634.

Sequence in context: A009619 A012024 A349008 * A193217 A329550 A208137

Adjacent sequences: A366632 A366633 A366634 * A366636 A366637 A366638

Keyword

nonn

Author

Sean A. Irvine, Oct 15 2023

Status

approved