A017205 a(n) = (9*n + 3)^9.

19683, 5159780352, 794280046581, 19683000000000, 208728361158759, 1352605460594688, 6351461955384057, 23762680013799936, 75084686279296875, 208215748530929664, 520411082988487293, 1195092568622310912, 2558036924386500591, 5159780352000000000, 9892530380752880769

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (10,-45,120,-210,252,-210,120,-45,10,-1).

Crossrefs

Cf. A013667, A016785, A017197.

Programs

Magma

[(9*n+3)^9: n in [0..20]]; // Vincenzo Librandi, Jul 23 2011

Mathematica

Table[(9*n + 3)^9, {n, 0, 20}] (* Amiram Eldar, Oct 03 2024 *)

Formula

From Amiram Eldar, Oct 03 2024: (Start)

a(n) = A017197(n)^9 = 3^9 * A016785(n).

Sum_{n>=0} 1/a(n) = 1618*Pi^9/(1098337086315*sqrt(3)) + 9841*zeta(9)/387420489. (End)