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Squares of odd octagonal numbers.
4

%I #16 Apr 16 2022 11:35:47

%S 1,441,4225,17689,50625,116281,231361,416025,693889,1092025,1640961,

%T 2374681,3330625,4549689,6076225,7958041,10246401,12996025,16265089,

%U 20115225,24611521,29822521,35820225,42680089,50481025,59305401

%N Squares of odd octagonal numbers.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).

%F 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

%F a(n) = ((1 + 2*n)*(1 + 6*n))^2. - _Stefano Spezia_, Apr 16 2022

%Y Cf. A000567, A014641, A014642, A014794.

%K nonn,easy

%O 0,2

%A _Mohammad K. Azarian_

%E More terms from _Patrick De Geest_, Aug 15 2000