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A025317 Numbers that are the sum of 2 distinct nonzero squares in 7 or more ways. 5
27625, 32045, 40885, 45305, 47125, 55250, 58565, 60125, 61625, 64090, 66625, 67405, 69745, 71825, 77285, 78625, 80665, 81770, 86125, 87125, 90610, 91205, 93925, 94250, 98345, 98605, 99125, 99905, 101065, 105625, 107185, 110500, 111605, 112625 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A025298. But sequences A025317 and A025298 are different. 2*5^12 = 488281250 = 15625^2 + 15625^2 (not distinct squares) = 14395^2 + 16765^2 = 10625^2 + 19375^2 = 9125^2 + 20125^2 = 4775^2 + 21575^2 = 3125^2 + 21875^2 = 1457^2 + 22049^2 is not in A025317. - Vaclav Kotesovec, Feb 27 2016

Numbers in A025298 but not in A025317 are exactly those numbers of the form 2*p_1^(2*a_1)*p_2^(2*a_2)*...*p_m^(2*a_m)*q^12 where p_i are primes of the form 4k+3 and q is a prime of the form 4k+1.  Thus 2*5^12 is the smallest term in A025298 that is not in A025317. - Chai Wah Wu, Feb 27 2016

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Index entries for sequences related to sums of squares

MATHEMATICA

nn = 112625; t = Table[0, {nn}]; lim = Floor[Sqrt[nn - 1]]; Do[num = i^2 + j^2; If[num <= nn, t[[num]]++], {i, lim}, {j, i - 1}]; Flatten[Position[t, _?(# >= 7 &)]] (* T. D. Noe, Apr 07 2011 *)

CROSSREFS

Sequence in context: A224110 A251958 A025298 * A025299 A025318 A025291

Adjacent sequences:  A025314 A025315 A025316 * A025318 A025319 A025320

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified December 14 22:42 EST 2019. Contains 329987 sequences. (Running on oeis4.)