A014793 Squares of odd octagonal numbers.

1, 441, 4225, 17689, 50625, 116281, 231361, 416025, 693889, 1092025, 1640961, 2374681, 3330625, 4549689, 6076225, 7958041, 10246401, 12996025, 16265089, 20115225, 24611521, 29822521, 35820225, 42680089, 50481025, 59305401

Offset

0,2

Links

Table of n, a(n) for n=0..25.

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Formula

G.f.: (-25*x^4 - 964*x^3 - 2030*x^2 - 436*x - 1)/(x-1)^5. - Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009

a(n) = ((1 + 2*n)*(1 + 6*n))^2. - Stefano Spezia, Apr 16 2022

Crossrefs

Cf. A000567, A014641, A014642, A014794.

Sequence in context: A343827 A250808 A202400 * A264305 A321337 A206467

Adjacent sequences: A014790 A014791 A014792 * A014794 A014795 A014796

Keyword

nonn,easy

Author

Mohammad K. Azarian

Extensions

More terms from Patrick De Geest, Aug 15 2000

Status

approved