A277385 Records in A277384.

15, 33, 65, 105, 153, 209, 273, 345, 425, 513, 609, 713, 825, 945, 1073, 1209, 1353, 1505, 1665, 1833, 2009, 2193, 2385, 2585, 2793, 3009, 3233, 3465, 3705, 3953, 4209, 4473, 4745, 5025, 5313, 5609, 5913, 6225, 6545, 6873, 7209, 7553, 7905, 8265, 8633, 9009

Offset

1,1

Comments

Essentially the same as A145923. - R. J. Mathar, Oct 23 2016

Links

Colin Barker, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Formula

G.f.: x*(15 -12*x +11*x^2 -6*x^3) / (1-x)^3.

E.g.f.: 7 + 6*x + (4*x^2 + 16*x - 7)*exp(x). - G. C. Greubel, Oct 12 2016

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>4.

a(n) = 4*n^2 + 12*n - 7 for n>1.

Mathematica

Join[{15}, LinearRecurrence[{3, -3, 1}, {33, 65, 105}, 25]] (* or *) Join[{15}, Table[4*n^2 + 12*n - 7, {n, 2, 25}]] (* G. C. Greubel, Oct 12 2016 *)

Prog

(PARI) Vec(x*(15-12*x+11*x^2-6*x^3)/(1-x)^3 + O(x^60))

Crossrefs

Cf. A277384.

Sequence in context: A231371 A228318 A228321 * A108517 A211327 A222179

Adjacent sequences: A277382 A277383 A277384 * A277386 A277387 A277388

Keyword

nonn,easy

Author

Colin Barker, Oct 12 2016

Status

approved