A017030 a(n) = (7*n + 4)^2.

16, 121, 324, 625, 1024, 1521, 2116, 2809, 3600, 4489, 5476, 6561, 7744, 9025, 10404, 11881, 13456, 15129, 16900, 18769, 20736, 22801, 24964, 27225, 29584, 32041, 34596, 37249, 40000, 42849, 45796

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 (3,-3,1).

Programs

Magma

[(7*n+4)^2: n in [0..40] ]; // Vincenzo Librandi, Jul 16 2011

Maple

A017030:=n->(7*n+4)^2; seq(A017030(n), n=0..100); # Wesley Ivan Hurt, Nov 11 2013

Mathematica

Table[(7n+4)^2, {n,0,100}] (* Wesley Ivan Hurt, Nov 11 2013 *)
LinearRecurrence[{3,-3,1},{16,121,324},40] (* Harvey P. Dale, May 25 2019 *)

PARI

a(n)=(7*n+4)^2 \\ Charles R Greathouse IV, Jun 17 2017

Formula

a(n) = A017029(n)^2. - Michel Marcus, Nov 11 2013

Sum{n>=0} 1/a(n) = psi'(4/7)/49 = 0.080438723... - R. J. Mathar, May 07 2024