OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Andrásfai Graph
Eric Weisstein's World of Mathematics, Wiener Index
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = (5*n - 4)*(3*n - 1)/2.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
G.f.: (x (-1 - 12 x - 2 x^2))/(-1 + x)^3.
MATHEMATICA
Table[(5 n - 4) (3 n - 1)/2, {n, 20}]
LinearRecurrence[{3, -3, 1}, {1, 15, 44}, 20]
CoefficientList[Series[(-1 - 12 x - 2 x^2)/(-1 + x)^3, {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Sep 07 2017
STATUS
approved