A062788 Squares of the form 5n*(n-1)+1.
1, 361, 116281, 37442161, 12056259601, 3882078149401, 1250017107847561, 402501626648765281, 129604273763794572961, 41732173650315203728201, 13437630311127731805907801, 4326875228009479326298583761, 1393240385788741215336338063281
Offset: 1
Links
- Index entries for linear recurrences with constant coefficients, signature (323,-323,1).
Programs
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PARI
for(n=1,10^8,x=(5*n*(n-1)+1); if(issquare(x),print(x)))
Formula
a(n) = A049683(2*n-1) = (1/16) * (Lucas(12*n-6) - 2). - Joerg Arndt, Apr 09 2023
From Chai Wah Wu, Apr 17 2024: (Start)
a(n) = 323*a(n-1) - 323*a(n-2) + a(n-3) for n > 3.
G.f.: x*(-x^2 - 38*x - 1)/((x - 1)*(x^2 - 322*x + 1)). (End)
Extensions
More terms from Sean A. Irvine, Apr 08 2023