OFFSET
1,2
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,38,0,0,-1).
FORMULA
a(n) = 38*a(n-3)-a(n-6).
G.f.: x*(1-x)*(1+4*x+17*x^2+4*x^3+x^4)/(1-38*x^3+x^6). [Colin Barker, Jun 13 2012]
EXAMPLE
25 is a term of the sequence since 10*25^2-9 = 6241 = 79^2.
MATHEMATICA
LinearRecurrence[{0, 0, 38, 0, 0, -1}, {1, 3, 13, 25, 111, 493}, 50] (* Paolo Xausa, Mar 18 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
John W. Layman, May 20 2003
EXTENSIONS
More terms from Bruno Berselli, Jan 29 2013
STATUS
approved