A168550 Natural numbers k for which 1 + 2*k^3 is prime.

1, 2, 5, 6, 9, 11, 12, 20, 21, 26, 27, 29, 30, 32, 35, 44, 57, 59, 60, 71, 72, 77, 86, 92, 95, 96, 99, 107, 111, 120, 134, 140, 149, 150, 152, 159, 162, 164, 165, 170, 185, 186, 191, 192, 197, 204, 221, 227, 231, 237, 246, 249, 252, 260, 264, 266, 269, 275, 290, 297

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 29 2009

Keywords

• nonn

Examples

			20 is a term because 1 + 2*20^3 = 16001 is prime.
		

Links

• Zak Seidov, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A201107, A033562, A049408.

Programs

Maple

isA168550 := proc(n) isprime(1+2*n^3) ; end proc: for n from 1 to 400 do if isA168550(n) then printf("%d,",n) ; end if; end do: # R. J. Mathar, Nov 30 2009

Mathematica

Select[Range[300],PrimeQ[1+2#^3]&] (* Harvey P. Dale, Jan 13 2022 *)

Extensions

Terms beyond 21 from R. J. Mathar, Nov 30 2009

Example corrected by Jon E. Schoenfield, May 11 2019