This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A264031 #11 Nov 25 2015 21:33:35 %S A264031 1,2,3,1,2,3,4,2,1,4,5,3,2,5,6,1,3,2,7,5,4,3,8,6,1,4,3,7,6,5,4,2,7,3, %T A264031 5,1,8,7,6,5,2,8,4,6,5,9,8,3,1,2,9,5,7,6,10,9,3,7,5,10,2,8,7,1,10,3,8, %U A264031 6,11,7,9,2,4,11,3,9,7,12,8,5,1 %N A264031 Minimum of the sum r + s of the coefficients of a linear combination of consecutive squares r*k^2 + s*(k+1)^2 equals to n, with r, s and k >=0. %C A264031 Every number n >= (k+2)*(k+1)*k*(k-1) - 1 = A069756(k) is of the form r*k^2 + s*(k+1)^2 with r, s and k positive integers. For any n >= 1, a(n) gives the minimum value of r + s for n = r*k^2 + s*(k+1)^2. %F A264031 a(k^2) = 1, a(A001105(k)) = 2 for k > 0 and a(A230812(k)) = 2; for any other values, a(n) >= 3. %e A264031 7 = 2^2 + 3*1^2, the sum of the coefficients of the linear combination is 1+3 = 4; The only other linear combination of consecutive squares giving 7 is 7*1^2 + 0, thus a(7) = 4, the minimum sum of the coefficients. %Y A264031 Cf. A001105, A069756, A230812. %K A264031 nonn %O A264031 1,2 %A A264031 _Jean-Christophe Hervé_, Nov 01 2015