OFFSET
0,2
COMMENTS
Numbers k such that 275*k + 1 is a square. The set of the integer square roots of 275*k + 1 is a superset of A377165.
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,0,2,-2,0,0,-1,1).
FORMULA
MATHEMATICA
CoefficientList[Series[x*(21 + 123*x + 129*x^2 + 4*x^3 + 129*x^4 + 123*x^5 + 21*x^6)/((1 - x)^3*(1 + x + x^2 + x^3)^2), {x, 0, 45}], x]
CROSSREFS
KEYWORD
nonn,easy,new
AUTHOR
Stefano Spezia, Oct 18 2024
STATUS
approved