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Number of partitions of n into 5 distinct nonzero squares.
8

%I #18 Feb 03 2021 15:43:54

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

%T 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,

%U 0,0,0,0,0,0,0,1,0,0,0,1,0,0,1,0,0,0,0,1,1,0,1,0,0,0,1,1,0,0,0,1,1,0,0,2,0,0,1,0

%N Number of partitions of n into 5 distinct nonzero squares.

%H David A. Corneth, <a href="/A025444/b025444.txt">Table of n, a(n) for n = 0..9999</a>

%H <a href="/index/Su#ssq">Index entries for sequences related to sums of squares</a>

%F a(n) = [x^n y^5] Product_{k>=1} (1 + y*x^(k^2)). - _Ilya Gutkovskiy_, Apr 22 2019

%e a(111) = 2 via 1 + 4 + 9 + 16 + 81 = 1 + 9 + 16 + 36 + 49. - _David A. Corneth_, Feb 02 2021

%p From _R. J. Mathar_, Oct 18 2010: (Start)

%p A025444aux := proc(n,m,nmax) local a,m,upn,lv ; if m = 1 then if issqr(n) and nmax^2 >= n and n >= 1 then return 1; else return 0; end if; else a := 0 ; for upn from 1 to nmax do lv := n-upn^2 ; if lv <0 then break; end if; a := a + procname(lv,m-1,upn-1) ; end do: return a; end if; end proc:

%p A025444 := proc(n) A025444aux(n,5,n) ; end proc: (End)

%Y Cf. A000290, A008452, A010052, A025433, A025441, A025442, A025443, A025444, A045851, A340946, A340988, A340998, A340999, A341000, A341001.

%Y Column k=5 of A341040.

%K nonn,look

%O 0,104

%A _David W. Wilson_