A063751 a(n) = phi(A002477(n)).

1, 110, 7992, 1111000, 119998800, 5759994240, 1229137654864, 108799998912000, 8007983991992016, 1090799999890920000, 123450846932098824864, 5702399999994297600000, 1195941578346547072508832, 111739686239998882603137600, 7532766719999992467233280000

Offset: 1

Author

Jason Earls, Aug 11 2001

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..352 (terms 1..81 from Harry J. Smith)

Crossrefs

Cf. A000010, A000042, A002477.

Programs

Mathematica

EulerPhi[((10^Range[20] - 1)/9)^2] (* Paolo Xausa, Nov 19 2024 *)

PARI

j=[]; for(n=0,25,j=concat(j,eulerphi( ((10^(n+1)-1)/9)^2) )); j

PARI

{ for (n=0, 80, a=eulerphi(((10^(n + 1) - 1)/9)^2); write("b063751.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 29 2009

Formula

a(n) = A000042(n) * phi(A000042(n)). - Amiram Eldar, Nov 19 2024

Extensions

Offset corrected by Amiram Eldar, Nov 19 2024