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 A174069 Numbers that can be written as a sum of at least 2 squares of consecutive positive integers. 12
 5, 13, 14, 25, 29, 30, 41, 50, 54, 55, 61, 77, 85, 86, 90, 91, 110, 113, 126, 135, 139, 140, 145, 149, 174, 181, 190, 194, 199, 203, 204, 221, 230, 245, 255, 265, 271, 280, 284, 285, 294, 302, 313, 330, 355, 365, 366, 371, 380, 384, 385, 415, 421, 434, 446, 451 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers are listed without multiplicity: 365 is the first term that is the sum of two or more squares in more than one way. See A062681 for other numbers of that form. - M. F. Hasler, Dec 22 2013 A subsequence of A212016. This sequence focuses on the squares of consecutive positive integers. - Altug Alkan, Dec 24 2015 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 EXAMPLE 5 = 1^2 + 2^2 13 = 2^2 + 3^2 14 = 1^2 + 2^2 + 3^2 25 = 3^2 + 4^2 MATHEMATICA max = 50^2; lst = {}; Do[z = n^2; Do[z += (n + x)^2; If[z > max, Break[]]; AppendTo[lst, z], {x, max/2}], {n, max/2}]; Union[lst] PROG (PARI) N=20; a=[]; for(i=2, N, for(k=1, i-1, if(N^2*2>t=sum(j=i-k, i, j^2), a=setunion(a, Set(t)), break))); a \\ M. F. Hasler, Dec 22 2013 CROSSREFS Cf. A111774, A138591, A151557 (subset of squares), A163251 (subset of primes). See also A062681, A212016. Sequence in context: A191382 A291792 A292565 * A020996 A090759 A090758 Adjacent sequences:  A174066 A174067 A174068 * A174070 A174071 A174072 KEYWORD nonn,easy AUTHOR Vladimir Joseph Stephan Orlovsky, Mar 06 2010 EXTENSIONS Name edited by Altug Alkan, Dec 24 2015 STATUS approved

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Last modified May 30 18:03 EDT 2020. Contains 334728 sequences. (Running on oeis4.)