OFFSET
0,3
COMMENTS
Equals the row sums of triangle A232266.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..81
FORMULA
EXAMPLE
Illustrate a(n) = Sum_{k=1..n} A006456(n^2-k^2):
a(1) = 1 = 1;
a(2) = 2 = 1 + 1;
a(3) = 11 = 7 + 3 + 1;
a(4) = 124 = 88 + 30 + 5 + 1;
a(5) = 2870 = 2024 + 710 + 124 + 11 + 1;
a(6) = 133462 = 94137 + 33033 + 5767 + 502 + 22 + 1;
a(7) = 12477207 = 8800750 + 3088365 + 539192 + 46832 + 2024 + 43 + 1; ...
MAPLE
b:= proc(n) option remember; local i; if n=0 then 1
else 0; for i while i^2<=n do %+b(n-i^2) od fi
end:
a:= n-> b(n^2):
seq(a(n), n=0..17); # Alois P. Heinz, Aug 12 2017
MATHEMATICA
b[0] = 1; b[n_] := b[n] = Sum[b[n-k], {k, Select[Range[n], IntegerQ[ Sqrt[#]]&]}];
a[n_] := b[n^2];
Table[a[n], {n, 0, 16}] (* Jean-François Alcover, Jun 09 2018 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Apr 05 2013
STATUS
approved