A239388 Values of n such that n^2 + d^2 is prime for a record first value of d.

1, 3, 8, 9, 12, 23, 30, 48, 63, 114, 141, 408, 651, 1173, 2697, 12639, 30963, 53343, 159537, 283209, 289131, 335511, 601398, 1832421, 2594214, 3533079, 4013361, 15717618, 17449677, 57532827, 186891843, 226385511, 231177657, 242117967

Offset

1,2

Comments

See A239389 for the corresponding values of d.

Links

Table of n, a(n) for n=1..34.

Mathematica

leastK[n_] := Module[{k = 1}, While[! PrimeQ[n^2 + k^2], k++]; k]; nn = 10000; t = {}; kMax = 0; Do[k = leastK[n]; If[k > kMax, kMax = k; AppendTo[t, {n, k}]], {n, nn}]; Transpose[t][[1]]

Crossrefs

Cf. A069003 (least number d such that n^2 + d^2 is prime).

Sequence in context: A165289 A066494 A082721 * A259850 A071677 A084747

Adjacent sequences: A239385 A239386 A239387 * A239389 A239390 A239391

Keyword

nonn,more

Author

T. D. Noe, Mar 18 2014

Extensions

a(24)-a(31) from Giovanni Resta, Mar 18 2014

a(32)-a(34) from Emmanuel Vantieghem, Jan 13 2017

Status

approved