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
Links
- 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
Extensions
More terms from Patrick De Geest, Aug 15 2000