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A025414 a(n) is the smallest number that is the sum of 3 nonzero squares in exactly n ways. 7
3, 27, 54, 129, 194, 209, 341, 374, 614, 594, 854, 1106, 1314, 1154, 1286, 1746, 1634, 1881, 2141, 2246, 2609, 2889, 3461, 3366, 3449, 3506, 4241, 4289, 5066, 4826, 5381, 5606, 6569, 5561, 6254, 7601, 8186, 8069, 8714, 8126, 9434, 8921, 8774, 11066, 11574 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A025427(a(n)) = n and A025427(m) != n for m < a(n). - Reinhard Zumkeller, Feb 26 2015

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000

Index entries for sequences related to sums of squares

EXAMPLE

54 is the smallest number having three partitions into nonzero squares: 54 = 1+4+49 = 4+25+25 = 9+9+36.

MATHEMATICA

lim=200; nLst=Table[0, {lim^2}]; Do[n=a^2+b^2+c^2; If[n>0 && n<lim^2, nLst[[n]]++ ], {a, lim}, {b, a, Sqrt[lim^2-a^2]}, {c, b, Sqrt[lim^2-a^2-b^2]}]; u=Union[nLst]; kMax=First[Complement[1+Range[u[[ -1]]], u]]-1; Table[First[Flatten[Position[nLst, k]]], {k, kMax}] (T. D. Noe)

PROG

(Haskell)

import Data.List (elemIndex); import Data.Maybe (fromJust)

a025414 = fromJust . (`elemIndex` a025427_list)

-- Reinhard Zumkeller, Feb 26 2015

CROSSREFS

Cf. A094740 (n having a unique partition into three positive squares), A095812 (greatest number having exactly n partitions into three positive squares).

Cf. A025427.

Sequence in context: A172969 A147267 A071183 * A201276 A053360 A176963

Adjacent sequences:  A025411 A025412 A025413 * A025415 A025416 A025417

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified November 18 01:20 EST 2018. Contains 317279 sequences. (Running on oeis4.)