A016948 a(n) = (6*n + 3)^4.

81, 6561, 50625, 194481, 531441, 1185921, 2313441, 4100625, 6765201, 10556001, 15752961, 22667121, 31640625, 43046721, 57289761, 74805201, 96059601, 121550625, 151807041, 187388721, 228886641, 276922881, 332150625, 395254161, 466948881, 547981281, 639128961

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..2000

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Formula

From Amiram Eldar, Mar 30 2022: (Start)

a(n) = A016945(n)^4 = A016946(n)^2.

a(n) = 3^4*A016756(n).

Sum_{n>=0} 1/a(n) = Pi^4/7776. (End)

Mathematica

a[n_] := (6*n + 3)^4; Array[a, 50, 0] (* Amiram Eldar, Mar 30 2022 *)

Prog

(Magma) [(6*n+3)^4: n in [0..50]]; // Vincenzo Librandi, May 05 2011

Crossrefs

Cf. A000583, A016756, A016945, A016946, A016947.

Sequence in context: A250612 A228974 A178513 * A206993 A223791 A206935

Adjacent sequences: A016945 A016946 A016947 * A016949 A016950 A016951

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved