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A006339 Least hypotenuse of n distinct Pythagorean triangles. 29
1, 5, 25, 125, 65, 3125, 15625, 325, 390625, 1953125, 1625, 48828125, 4225, 1105, 6103515625, 30517578125, 40625, 21125, 3814697265625, 203125, 95367431640625, 476837158203125, 5525, 11920928955078125, 274625, 5078125, 1490116119384765625, 528125, 25390625, 186264514923095703125 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
Ray Chandler, Table of n, a(n) for n = 0..1438 (a(1439) exceeds 1000 digits).
Eric Weisstein's World of Mathematics, Circle Lattice Points
Eric Weisstein's World of Mathematics, Pythagorean Triple
MATHEMATICA
oneModFourPrimes[1] = 5;
oneModFourPrimes[n_] := oneModFourPrimes[n] = NestWhile[NextPrime, NextPrime[oneModFourPrimes[n - 1]], Mod[#, 4] != 1 & ];
factorizations[1, limit_] = {{}};
factorizations[n_, limit_] := factorizations[n, limit] = Join @@ Table[Prepend[#, d]& /@ factorizations[n/d, d], {d, Select[Rest[Divisors[n]], # <= limit & ]}];
leastHypotenuse[n_] := Min[(Times @@ (Array[oneModFourPrimes, Length[#]]^((# - 1)/2)) & ) /@ factorizations[2*n + 1, 2*n + 1]];
Array[leastHypotenuse, 30, 0]
(* Albert H. Mao, Jan 06 2012 *)
CROSSREFS
Except for offset, same as A046112.
Sequence in context: A036156 A097756 A046112 * A032534 A036151 A271380
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified August 18 11:16 EDT 2024. Contains 375265 sequences. (Running on oeis4.)