OFFSET
1,1
REFERENCES
Stan Wagon, Mathematica in Action, Springer, 2000 (2nd ed.), Ch. 17.5, pp. 375-378.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
EXAMPLE
338 = 7^2 + 17^2 = 13^2 + 13^2;
410 = 7^2 + 19^2 = 11^2 + 17^2.
MAPLE
Prime2PairsSum := p -> select(x ->`if`(andmap(isprime, x), true, false), numtheory:-sum2sqr(p)):
for n from 2 to 10^6 do
if nops(Prime2PairsSum(n)) = 2 then print(n, Prime2PairsSum(n)) fi;
od;
MATHEMATICA
Select[Range@10000, Length[Select[ PowersRepresentations[#, 2, 2], And @@ PrimeQ[#] &]] == 2 &] (* Giovanni Resta, Jun 11 2013 *)
PROG
(PARI) select( is_A226539(n)={#[0|t<-sum2sqr(n), isprime(t[1])&&isprime(t[2])]==2}, [1..10^4]) \\ For more efficiency, apply selection to A045636. See A133388 for sum2sqr(). - M. F. Hasler, Dec 12 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Henk Koppelaar, Jun 10 2013
EXTENSIONS
a(25)-a(44) from Giovanni Resta, Jun 11 2013
STATUS
approved