A108924 J(n)^2+J(n+1)^2, with J(n) the Jacobsthal number A001045(n).

1, 2, 10, 34, 146, 562, 2290, 9074, 36466, 145522, 582770, 2329714, 9321586, 37280882, 149134450, 596515954, 2386107506, 9544342642, 38177545330, 152709831794, 610840026226, 2443358706802, 9773437623410, 39093744901234

Offset

0,2

Links

Table of n, a(n) for n=0..23.

Index entries for linear recurrences with constant coefficients, signature (3,6,-8).

Formula

G.f.: (1-x-2x^2)/((1-x)(1-4x)(1+2x)); a(n)=3a(n-1)+6a(n-2)-8a(n-3); a(n)=(5/9)4^n+(2/9)(-2)^n+2/9.

a(0)=1, a(1)=2, a(2)=10, a(n)=3*a(n-1)+6*a(n-2)-8*a(n-3). - Harvey P. Dale, Apr 11 2013

Mathematica

Total/@Partition[LinearRecurrence[{1, 2}, {0, 1}, 40]^2, 2, 1] (* or *) LinearRecurrence[ {3, 6, -8}, {1, 2, 10}, 40] (* Harvey P. Dale, Apr 11 2013 *)

Crossrefs

Sequence in context: A306099 A192378 A052965 * A281097 A221492 A356389

Adjacent sequences: A108921 A108922 A108923 * A108925 A108926 A108927

Keyword

easy,nonn

Author

Paul Barry, Jul 17 2005

Status

approved