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A274044
Squarefree numbers that are the sum of two squares in more than one way.
2
65, 85, 130, 145, 170, 185, 205, 221, 265, 290, 305, 365, 370, 377, 410, 442, 445, 481, 485, 493, 505, 530, 533, 545, 565, 610, 629, 685, 689, 697, 730, 745, 754, 785, 793, 865, 890, 901, 905, 949, 962, 965, 970, 985, 986, 1010, 1037, 1066, 1073, 1090, 1105, 1130, 1145
OFFSET
1,1
COMMENTS
Squarefree numbers that are the sum of two nonzero squares in more than one way.
LINKS
FORMULA
A005117 INTERSECT A007692. - R. J. Mathar, Feb 01 2017
EXAMPLE
65 is a term because 65 = 5*13 = 1^2 + 8^2 = 4^2 + 7^2.
PROG
(PARI) isA007692(n) = {nb = 0; lim = sqrtint(n); for (x=1, lim, if ((n-x^2 >= x^2) && issquare(n-x^2), nb++); ); nb >= 2; }
lista(nn) = for(n=1, nn, if(isA007692(n) && issquarefree(n), print1(n, ", ")));
CROSSREFS
KEYWORD
nonn
AUTHOR
Altug Alkan, Jun 07 2016
STATUS
approved