A081351 - OEIS

A081351

First row in square maze array of natural numbers A081349.

1, 8, 9, 24, 25, 48, 49, 80, 81, 120, 121, 168, 169, 224, 225, 288, 289, 360, 361, 440, 441, 528, 529, 624, 625, 728, 729, 840, 841, 960, 961, 1088, 1089, 1224, 1225, 1368, 1369, 1520, 1521, 1680, 1681, 1848, 1849, 2024, 2025, 2208, 2209, 2400, 2401, 2600

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

Interleaves the odd squares A016754 with 8 times the triangular numbers A000217.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (1,2,-2,-1,1).

FORMULA

a(n) = (n+1)*(n+2)-(n+1)*(-1)^n = 2*C(n+2,2)-C(n+1,1)*(-1)^n.

G.f.: (x^3-x^2+7*x+1)/((1-x)^3*(1+x)^2). [Colin Barker, Sep 03 2012]

PROG