A226562 Numbers which are the sum of two squared primes in exactly three ways (ignoring order).
2210, 3770, 5330, 6290, 12818, 16490, 18122, 19370, 24050, 24650, 26690, 32810, 33410, 34970, 36530, 39650, 39770, 44642, 45050, 45890, 49010, 50690, 51578, 57770, 59450, 61610, 63050, 66170, 67490, 72410, 73610, 74210, 80330, 85202, 86210, 86330, 88010
Offset: 1
Keywords
Examples
2210 = 19^2 + 43^2 = 23^2 + 41^2 = 29^2 + 37^2;
References
- Stan Wagon, Mathematica in Action, Springer, 2000 (2nd ed.), Ch. 17.5, pp. 375-378.
Links
- Zak Seidov, Table of n, a(n) for n = 1..2464 (all terms up to 10^7).
Crossrefs
Programs
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Maple
Prime2PairsSum := s -> select( x -> `if`(andmap(isprime, x), true, false), numtheory:-sum2sqr(s)): for n from 2 to 10 do if nops(Prime2PairsSum(n)) = 3 then print(n,Prime2PairsSum(n)) fi od;
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Mathematica
Select[Range@20000, Length[Select[ PowersRepresentations[#, 2, 2], And @@ PrimeQ[#] &]] == 3 &] (* Giovanni Resta, Jun 11 2013 *)
Extensions
a(22)-a(37) from Giovanni Resta, Jun 11 2013
Comments