OFFSET
0,1
COMMENTS
For n > 2, also the detour index of the n-book graph.
LINKS
Kelvin Voskuijl, Table of n, a(n) for n = 0..10000
Eric Weisstein's World of Mathematics, Book Graph.
Eric Weisstein's World of Mathematics, Detour Index.
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = 3*a(n-1)-3*a(n-2)+a(n-3).
G.f.: (-3-17*x-6*x^2)/(-1+x)^3.
MATHEMATICA
Table[13 n^2 + 10 n + 3, {n, 0, 20}]
LinearRecurrence[{3, -3, 1}, {26, 75, 150}, {0, 20}]
CoefficientList[Series[(-3 - 17 x - 6 x^2)/(-1 + x)^3, {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Sep 04 2025
STATUS
approved