A351419 If n = p_1^e_1 * ... * p_k^e_k, where p_1 < ... < p_k are primes, then a(n) is obtained by replacing the last factor p_k^e_k by (p_k - 1)^(e_k + 1); a(1) = 1.

1, 1, 4, 1, 16, 8, 36, 1, 8, 32, 100, 16, 144, 72, 48, 1, 256, 16, 324, 64, 108, 200, 484, 32, 64, 288, 16, 144, 784, 96, 900, 1, 300, 512, 180, 32, 1296, 648, 432, 128, 1600, 216, 1764, 400, 144, 968, 2116, 64, 216, 128, 768, 576, 2704, 32, 500, 288, 972, 1568

Offset

1,3

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

a[n_] := Module[{f = FactorInteger[n]}, n*(f[[-1, 1]] - 1)^(f[[-1, 2]] + 1)/f[[-1, 1]]^f[[-1, 2]]]; a[1] = 1; Array[a, 100] (* Amiram Eldar, Feb 11 2022 *)

Crossrefs

Inspired by A351168.

Cf. A351425.

Sequence in context: A138681 A038231 A104855 * A303054 A143496 A143697

Adjacent sequences: A351416 A351417 A351418 * A351420 A351421 A351422

Keyword

nonn

Author

N. J. A. Sloane, Feb 11 2022

Status

approved