A273874 - OEIS

%I #27 May 07 2021 09:34:33

%S 5,1,2,0,2,0,0,0,0,2,5,1,12,0,3,0,3,0,0,0,0,0,53,1,1,1,2,0,4,0,0,0,5,

%T 2,0,0,2,0,3,0,5,0,0,5,0,0,73,1,3,1,2,0,2,0,5,0,0,2,97,1,4,0,0,0,2,5,

%U 0,0,30,0,0,0,1,1,4,0,0,0,0,0,0,2,26,0,6

%N Least positive integer k such that k^2 + (k+1)^2 + ... + (k+n-2)^2 + (k+n-1)^2 is the sum of two nonzero squares. a(n) = 0 if no solution exists.

%C Least positive integer k such that Sum_{i=0..n-1} (k+i)^2 = n*(6*k^2 + 6*k*n - 6*k + 2*n^2 - 3*n + 1)/6 is the sum of two nonzero squares. a(n) = 0 if no k exists for corresponding n.

%e a(1) = 5 because 5^2 = 3^2 + 4^2.

%e a(3) = 2 because 2^2 + 3^2 + 4^2 = 2^2 + 5^2.

%Y Cf. A000404, A034705.

%K nonn

%O 1,1

%A _Altug Alkan_, Jun 02 2016

%E a(7)-a(50) from _Giovanni Resta_, Jun 02 2016

%E More terms from _Jinyuan Wang_, May 02 2021