A016839 a(n) = (4*n+3)^3.

27, 343, 1331, 3375, 6859, 12167, 19683, 29791, 42875, 59319, 79507, 103823, 132651, 166375, 205379, 250047, 300763, 357911, 421875, 493039, 571787, 658503, 753571, 857375, 970299, 1092727, 1225043

Offset

0,1

Links

Ivan Panchenko, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Formula

G.f.: ( 27+235*x+121*x^2+x^3 ) / (x-1)^4 . - R. J. Mathar, Dec 03 2015

Sum_{n>=0} 1/a(n) = 7*zeta(3)/16 - Pi^3/64. - Amiram Eldar, Jun 28 2020

Mathematica

(4*Range[0, 30]+3)^3 (* or *) LinearRecurrence[{4, -6, 4, -1}, {27, 343, 1331, 3375}, 30] (* Harvey P. Dale, Jul 21 2018 *)

Prog

(PARI) a(n) = (4*n+3)^3; \\ Altug Alkan, Dec 03 2015

Crossrefs

Sequence in context: A038840 A226090 A032599 * A128831 A018797 A239220

Adjacent sequences: A016836 A016837 A016838 * A016840 A016841 A016842

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved