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A213721 Smallest prime that is the sum of four nonzero squares in exactly n ways. 2
2, 7, 31, 67, 97, 103, 157, 199, 277, 223, 307, 383, 439, 367, 547, 463, 673, 613, 577, 751, 643, 733, 787, 727, 853, 983, 997, 967, 1171, 1223, 1063, 1087, 1123, 1613, 1237, 1279, 1471, 1453, 1669, 1423, 1483, 1597, 1627, 1543, 1567, 1747, 2039, 1753, 1867, 1951 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..49.

Index entries for sequences related to sums of squares

EXAMPLE

a(2) = 31 because 31 = 2*1 + 4 + 25 = 4 + 3*9.

MATHEMATICA

lst = {}; Do[p = 2; While[True, If[PrimeQ[p] && Length@Select[PowersRepresentations[p, 4, 2], ! MemberQ[#, 0] &] == n, AppendTo[lst, p]; Break[]]; p++], {n, 0, 49}]; lst

CROSSREFS

Cf. A025416.

Sequence in context: A191073 A049576 A298169 * A102162 A059846 A343532

Adjacent sequences:  A213718 A213719 A213720 * A213722 A213723 A213724

KEYWORD

nonn

AUTHOR

Arkadiusz Wesolowski, Nov 02 2012

STATUS

approved

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Last modified October 20 04:52 EDT 2021. Contains 348099 sequences. (Running on oeis4.)