OFFSET
1,12
LINKS
Robert Israel, Table of n, a(n) for n = 1..5711
FORMULA
a(n) = Sum_{k=1..floor(n/5)} binomial(floor(n/3), 4*k)*binomial(ceiling(2*n/3), k). - Robert Israel, Feb 05 2017
MAPLE
f:= proc(n) local k;
add(binomial(floor(n/3), 4*k/5)*binomial(n-floor(n/3), k/5), k=5..n, 5)
end proc:
map(f, [$1..60]); # Robert Israel, Feb 05 2017
PROG
(PARI) a(n)=sum(k=1, n\5, binomial(n\3, 4*k)*binomial(ceil(2*n/3), k)) \\ Charles R Greathouse IV, Feb 05 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved