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A175361 Partial sums of A000141.

%I A175361 #14 Jun 21 2024 17:23:22
%S A175361 1,13,73,233,485,797,1341,2301,3321,4197,5757,8157,10237,12277,15541,
%T A175361 19701,23793,27273,31653,38853,45405,50013,58173,68733,76957,84769,
%U A175361 94969,108089,120569,130673,144817,164017,180397,191917,209317,234277,252673,269113,293593
%N A175361 Partial sums of A000141.
%C A175361 The 6th row of A122510.
%F A175361 a(n^2) = A055412(n).
%F A175361 G.f.: theta_3(x)^6 / (1 - x). - _Ilya Gutkovskiy_, Feb 13 2021
%t A175361 CoefficientList[Series[EllipticTheta[3,x]^6/(1-x),{x,0,35}],x] (* _Stefano Spezia_, Jun 21 2024 *)
%o A175361 (Python)
%o A175361 from math import prod
%o A175361 from sympy import factorint
%o A175361 def A175361(n):
%o A175361     c = 1
%o A175361     for m in range(1,n+1):
%o A175361         f = [(p,e,(0,1,0,-1)[p&3]) for p,e in factorint(m).items()]
%o A175361         c += (prod((p**(e+1<<1)-a)//(p**2-a) for p, e, a in f)<<2)-prod(((k:=p**2*a)**(e+1)-1)//(k-1) for p, e, a in f)<<2
%o A175361     return c # _Chai Wah Wu_, Jun 21 2024
%Y A175361 Cf. A000141, A055412, A122510.
%K A175361 nonn
%O A175361 0,2
%A A175361 _R. J. Mathar_, Apr 24 2010