The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A215908 Smallest integer that can be represented as the sum of n squares of positive integers in at least n distinct ways. 2
 1, 50, 54, 52, 53, 54, 55, 56, 57, 61, 65, 66, 67, 68, 74, 78, 79, 81, 82, 83, 84, 88, 92, 93, 96, 98, 99, 100, 101, 102, 106, 107, 108, 112, 113, 114, 115, 116, 117, 121, 124, 125, 129, 130, 131, 132, 133, 134, 136, 137, 141, 142, 143, 147, 148, 149, 150, 151 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence differs from A052261 first at n=11: a(11) = 65 < A052261(11) = 67. 65 has 12 distinct representations (as the sum of 11 squares of positive integers) whereas 67 has exactly 11. LINKS Alois P. Heinz, Table of n, a(n) for n = 1..1000 EXAMPLE a(1) =  1 = 1^2. a(2) = 50 = 1^2+7^2 = 5^2+5^2. a(3) = 54 = 2^2+2*5^2 = 2*3^2+6^2 = 1^2+2^2+7^2. a(11) = 65 = 3*1^2+2*2^2+6*3^2 = 2*1^2+5*2^2+3*3^2+4^2 = 1^2+8*2^2+2*4^2 = 6*1^2+3*3^2+2*4^2 = 5*1^2+3*2^2+3*4^2 = 10*2^2+5^2 = 5*1^2+2*2^2+3*3^2+5^2 = 4*1^2+5*2^2+4^2+5^2 = 8*1^2+2*4^2+5^2 = 7*1^2+2*2^2+2*5^2 = 7*1^2+2^2+2*3^2+6^2 = 8*1^2+2*2^2+7^2. MAPLE b:= proc(n, i, t) option remember; `if`(n0, b(n, i-1, t), 0)+       `if`(i^2>n, 0, b(n-i^2, i, t-1)))))     end: a:= proc(n) local k;       for k while b(k, isqrt(k), n) 0, b[n, i-1, t], 0] + If[i^2 > n, 0, b[n-i^2, i, t-1]]]]]; a[n_] := Module[{k}, For[k = 1, b[k, Sqrt[k] // Floor, n] < n, k++]; k]; Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Dec 30 2013, translated from Maple *) CROSSREFS Cf. A052261. Sequence in context: A294297 A320673 A081646 * A052261 A295155 A118146 Adjacent sequences:  A215905 A215906 A215907 * A215909 A215910 A215911 KEYWORD nonn AUTHOR Alois P. Heinz, Aug 26 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 28 12:34 EDT 2020. Contains 337393 sequences. (Running on oeis4.)