OFFSET
0,2
LINKS
Indranil Ghosh, Table of n, a(n) for n = 0..436
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (194,-1).
FORMULA
a(n) = ((7+4*sqrt(3))^(2*n+1)-(7-4*sqrt(3))^(2*n+1))/(8*sqrt(3)). [simplified by Bruno Berselli, Oct 19 2012]
a(n) = floor(((7*sqrt(3) + 12)/24)*(56*sqrt(3) + 97)^n).
a(n+2) = 194*a(n+1) - a(n).
G.f.: (1-x)/(1-194*x+x^2). - Philippe Deléham, Nov 18 2008
EXAMPLE
a(1)=195 because 195 = sqrt((Sum_{k=1..337}k^2)/337) and 337 = A084231(1).
MATHEMATICA
LinearRecurrence[{194, -1}, {1, 195}, 20] (* Harvey P. Dale, Nov 10 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ignacio Larrosa Cañestro, May 20 2003
STATUS
approved