OFFSET
0,2
REFERENCES
A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (8,-28,56,-70,56,-28,8,-1).
FORMULA
a(n) = C(n+6, 6)*(5n+7)/7.
G.f.: (1+4*x)/(1-x)^8.
MATHEMATICA
CoefficientList[Series[(1 + 4 x)/(1 - x)^8, {x, 0, 50}], x] (* Vincenzo Librandi, Jul 30 2014 *)
Accumulate[CoefficientList[Series[(1+4x)/(1-x)^7, {x, 0, 40}], x]] (* or *) LinearRecurrence[{8, -28, 56, -70, 56, -28, 8, -1}, {1, 12, 68, 264, 810, 2112, 4884, 10296}, 30] (* Harvey P. Dale, Aug 21 2020 *)
PROG
(Magma) [((5*n+7)*Binomial(n+6, 6))/7: n in [0..60]]; // Vincenzo Librandi, Jul 30 2014
(PARI) a(n)=binomial(n+6, 6)*(5*n+7)/7 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Barry E. Williams, Dec 26 1999
STATUS
approved