A323891 a(n) is the number of partitions of 72*n + 42 into 10 odd squares.
2, 9, 22, 41, 68, 106, 154, 212, 285, 368, 477, 598, 741, 898, 1076, 1286, 1524, 1785, 2068, 2379, 2741, 3131, 3554, 4002, 4497, 5044, 5644, 6274, 6939, 7653, 8445, 9295, 10186, 11117, 12113, 13192, 14355, 15556, 16807, 18147, 19570, 21089, 22673, 24300, 26029, 27865, 29821, 31822, 33894, 36088
Offset: 0
Keywords
Examples
For n=0, 72*0+42 = 42 = 25+9+1+1+1+1+1+1+1+1 = 9+9+9+9+1+1+1+1+1+1, so a(0)=2. For n=1, 72*1+42 = 114 = 81+25+1+1+1+1+1+1+1+1 = 81+9+9+9+1+1+1+1+1+1 = 49+49+9+1+1+1+1+1+1+1 = 49+25+25+9+1+1+1+1+1+1 = 49+25+9+9+9+9+1+1+1+1 = 49+9+9+9+9+9+9+9+1+1 = 25+25+25+25+9+1+1+1+1+1 = 25+25+25+9+9+9+9+1+1+1 = 25+25+9+9+9+9+9+9+9+1, so a(1)=9.
References
- Laurențiu Panaitopol, Alexandru Gica, Arithmetic problems and number theory, Ed. Gil, Zalău, (2006), ch. 14, p. 85, pr. 32. (in Romanian).
Links
- Robert Israel, Table of n, a(n) for n = 0..2000
Crossrefs
Programs
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Magma
[#RestrictedPartitions(72*n+42, 10, {(2*d+1)^2:d in [0..100]}): n in [0..100]];
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Maple
S:= proc(n, k, m) option remember; local p,j; if k = 0 then if n = 0 then return 1 else return 0 fi elif m < 1 then return 0 elif n < k then return 0 elif n > k*m^2 then return 0 fi; if m^2 > n then p:= floor(sqrt(n)); if p::even then p:= p-1 fi; return procname(n, k, p) fi; add(procname(n-j*m^2,k-j,m-2), j=0..n/m^2) end proc: seq(S(72*n+42, 10, 72*n+42), n=0..100); # Robert Israel, Feb 24 2019
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Mathematica
a[n_] := IntegerPartitions[72n+42, {10}, Select[ Range[1, 72n+42, 2], IntegerQ@Sqrt@#&]] // Length; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Sep 19 2022 *)