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 A025442 Number of partitions of n into 3 distinct nonzero squares. 20
 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 2, 0, 0, 1, 1, 0, 0, 2, 1, 0, 0, 0, 2, 1, 0, 2, 1, 0, 0, 1, 0, 1, 1, 0, 2, 0, 0, 2, 2, 1, 0, 1, 2, 0, 0, 0, 2, 0, 0, 3, 0, 0, 1, 2, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,63 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..10000 Index entries for sequences related to sums of squares FORMULA a(n)>0 <=> n is in A004432. - M. F. Hasler, Feb 03 2013 a(n) = [x^n y^3] Product_{k>=1} (1 + y*x^(k^2)). - Ilya Gutkovskiy, Apr 22 2019 MAPLE b:= proc(n, i, t) option remember; `if`(n=0, `if`(t=0, 1, 0), `if`(i<1 or t<1, 0, `if`(i=1, 0, b(n, i-1, t))+ `if`(i^2>n, 0, b(n-i^2, i-1, t-1)))) end: a:= n-> b(n, isqrt(n), 3): seq(a(n), n=0..120); # Alois P. Heinz, Feb 07 2013 MATHEMATICA b[n_, i_, t_] := b[n, i, t] = If[n==0, If[t==0, 1, 0], If[i<1 || t<1, 0, If[i==1, 0, b[n, i-1, t]] + If[i^2 > n, 0, b[n-i^2, i-1, t-1]]]]; a[n_] := b[n, Sqrt[n] // Floor, 3]; Table[a[n], {n, 0, 120}] (* Jean-François Alcover, Oct 10 2015, after Alois P. Heinz *) PROG (PARI) A025442(n)={sum(x=1, sqrtint(n\3), sum(y=x+1, sqrtint((n-1-x^2)\2), issquare(n-x^2-y^2)))} \\ - M. F. Hasler, Feb 03 2013 CROSSREFS Cf. A024803, A025339, A001974, A004432. Column k=3 of A341040. Sequence in context: A159708 A144625 A224772 * A260118 A128582 A213185 Adjacent sequences: A025439 A025440 A025441 * A025443 A025444 A025445 KEYWORD nonn AUTHOR David W. Wilson STATUS approved

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Last modified April 12 14:01 EDT 2024. Contains 371635 sequences. (Running on oeis4.)