A028677 Pseudo Galois numbers for d=15.

1, 210, 10584000, 120522654000000, 308880278577360000000000, 178115698742031918598500000000000000, 23109857603759312583902403410250000000000000000000, 674644359535320835775869151538023145415195312500000000000000000000

Offset: 0

Author

Olivier Gérard

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..29

Crossrefs

Cf. A028668, A028670, A028671, A028672, A028674, A028676, A028678, A028680, A028682, A028683, A028684, A028686.

Programs

Mathematica

FoldList[ #1*15^#2 (15^#2-1)&, 1, Range[ 20 ] ]
a[n_] := 15^n * Product[15^n - 15^k, {k, 0, n-1}]; Array[a, 8, 0] (* Amiram Eldar, Jul 13 2025 *)

PARI

a(n) = 15^n * prod(k = 0, n-1, 15^n - 15^k); \\ Amiram Eldar, Jul 13 2025

Formula

a(n) = 15^n * Product_{k=0..n-1} (15^n - 15^k).

a(n) ~ c * 15^(n^2+n), where c = Product_{k>=1} (1 - 1/15^k) = 0.928890211614... . - Amiram Eldar, Jul 13 2025