A028400 a(n) = (2^n + 1)^2.

4, 9, 25, 81, 289, 1089, 4225, 16641, 66049, 263169, 1050625, 4198401, 16785409, 67125249, 268468225, 1073807361, 4295098369, 17180131329, 68720001025, 274878955521, 1099513724929, 4398050705409, 17592194433025

Offset

0,1

Links

Table of n, a(n) for n=0..22.

H. Bottomley, Illustration of initial terms

I. Strazdins, Universal affine classification of Boolean functions, Acta Applic. Math. 46 (1997), 147-167.

Index entries for linear recurrences with constant coefficients, signature (7,-14,8).

Formula

a(n) = A000051(n)^2. - R. J. Mathar, Nov 27 2015

G.f.: ( -4+19*x-18*x^2 ) / ( (x-1)*(2*x-1)*(4*x-1) ). - R. J. Mathar, Nov 27 2015

Prog

(PARI) a(n)=(2^n + 1)^2

Crossrefs

Sequence in context: A304167 A317975 A307396 * A237613 A220444 A355799

Adjacent sequences: A028397 A028398 A028399 * A028401 A028402 A028403

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved