A239390 Values of n such that n^2 + (n-d)^2 is prime for a record first value of d.

2, 4, 7, 16, 21, 29, 42, 69, 300, 301, 399, 651, 957, 5931, 8319, 11778, 13587, 13704, 15507, 37452, 37506, 62766, 94698, 182193, 217989, 227247, 306084, 312018, 318849, 530607, 4054218, 4643481, 5094039, 5393553, 7245414, 7811964, 9119988, 11927643, 24778644, 43709337, 55244217

Offset

1,1

Comments

See A239391 for the corresponding values of d.

Links

Chai Wah Wu, Table of n, a(n) for n = 1..44

Mathematica

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

Crossrefs

Cf. A069002 (least number d such that n^2 + (n-d)^2 is prime).

Sequence in context: A135131 A032363 A303749 * A338647 A372097 A361334

Adjacent sequences: A239387 A239388 A239389 * A239391 A239392 A239393

Keyword

nonn

Author

T. D. Noe, Mar 19 2014

Extensions

a(38)-a(41) from Chai Wah Wu, Feb 06 2020

Status

approved