A257721 Hexagonal numbers (A000384) that are the sum of two consecutive hexagonal numbers.

703, 810901, 935778691, 1079887798153, 1246189583289511, 1438101699228297181, 1659568114719871657003, 1915140166285032663883921, 2210070092324812974250387471, 2550418971402667887252283257253, 2943181282928586417076160628482131

Offset

1,1

Links

Colin Barker, Table of n, a(n) for n = 1..326

Index entries for linear recurrences with constant coefficients, signature (1155, -1155, 1).

Formula

a(n) = 1155*a(n-1)-1155*a(n-2)+a(n-3).

G.f.: -x*(x^2-1064*x+703) / ((x-1)*(x^2-1154*x+1)).

Example

703 is in the sequence because H(19) = 703 = 325+378 = H(13)+H(14).

Prog

(PARI) Vec(-x*(x^2-1064*x+703)/((x-1)*(x^2-1154*x+1)) + O(x^100))

Crossrefs

Cf. A251602, A257722, A257723, A257724.

Sequence in context: A161021 A283521 A334010 * A253396 A188370 A185571

Adjacent sequences: A257718 A257719 A257720 * A257722 A257723 A257724

Keyword

nonn,easy

Author

Colin Barker, May 06 2015

Status

approved