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A269928
Integers n that belong to more Pythagorean triples than preceding integers.
1
1, 3, 5, 12, 15, 24, 40, 48, 60, 120, 240, 360, 420, 720, 840, 1560, 1680, 2520, 3360, 5040, 8400, 9240, 10920, 15120, 18480, 21840, 27720, 32760, 36960, 43680, 55440, 65520, 109200, 110880, 120120, 166320, 196560, 221760, 240240, 360360, 480480, 720720, 1113840
OFFSET
1,2
COMMENTS
Called optimal P-numbers in Tripathi link.
PROG
(PARI) nbpt(n) = {oddn = n/(2^valuation(n, 2)); f = factor(oddn); for (k=1, #f~, if ((f[k, 1] % 4) != 1, f[k, 2] = 0); ); n1 = factorback(f); if (n % 2, (numdiv(n^2)+numdiv(n1^2))/2 -1, (numdiv((n/2)^2)+numdiv(n1^2))/2 -1); }
lista(nn) = {last = -1; for (n=1, nn, if ((new = nbpt(n)) > last, print1(n, ", "); last = new; ); ); }
CROSSREFS
Sequence in context: A080560 A260818 A151866 * A057587 A213036 A032438
KEYWORD
nonn
AUTHOR
Michel Marcus, Mar 08 2016
STATUS
approved