OFFSET
1,28
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
A023531[n_]:= SquaresR[1, 8n+9]/2;
Table[a[n], {n, 110}] (* G. C. Greubel, Jan 17 2022 *)
PROG
(Haskell)
a024316 n = sum $ take (div (n + 1) 2) $ zipWith (*) zs $ reverse zs
where zs = take n $ tail a023531_list
-- Reinhard Zumkeller, Feb 14 2015
(Magma)
A023531:= func< n | IsIntegral( (Sqrt(8*n+9) - 3)/2 ) select 1 else 0 >;
[ (&+[A023531(j)*A023531(n-j+1): j in [1..Floor((n+1)/2)]]) : n in [1..110]]; // G. C. Greubel, Jan 17 2022
(Sage)
def A023531(n):
if ((sqrt(8*n+9) -3)/2).is_integer(): return 1
else: return 0
[sum( A023531(j)*A023531(n-j+1) for j in (1..floor((n+1)/2)) ) for n in (1..110)] # G. C. Greubel, Jan 17 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved