OFFSET
1,1
COMMENTS
For the first of the corresponding seventeen consecutive positive integers, see A261935.
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,70,-70,-1,1).
FORMULA
G.f.: -x*(40*x^4+51*x^3-148*x^2+51*x+40) / ((x-1)*(x^4-70*x^2+1)).
EXAMPLE
40 is in the sequence because 40^2 + 41^2 = 5^2 + 6^2 + ... + 21^2.
MATHEMATICA
LinearRecurrence[{1, 70, -70, -1, 1}, {40, 91, 2743, 6364, 192004}, 20] (* Harvey P. Dale, Oct 17 2015 *)
PROG
(PARI) Vec(-x*(40*x^4+51*x^3-148*x^2+51*x+40)/((x-1)*(x^4-70*x^2+1)) + O(x^40))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Sep 06 2015
STATUS
approved