Numbers k such that 8k+1, 12k+1 and 24k+1 are primes and the last two are also of the form x^2 + 27y^2, so the tetrahedral number T(24k+1) is a Fermat pseudoprime to base 2.
A321867
Numbers k such that 8k+1, 12k+1 and 24k+1 are primes and the last two are also of the form x^2 + 27y^2, so the tetrahedral number T(24k+1) is a Fermat pseudoprime to base 2.
Terms
- a(0) =1179a(1) =1274a(2) =1895a(3) =4775a(4) =5304a(5) =5874a(6) =6525a(7) =6639a(8) =13035a(9) =16380a(10) =17424a(11) =18459a(12) =21239a(13) =21584a(14) =21714a(15) =22475a(16) =22715a(17) =22734a(18) =27410a(19) =28304a(20) =29340a(21) =29909a(22) =31755a(23) =32294a(24) =34700a(25) =37700a(26) =41525a(27) =42164a(28) =42929a(29) =42950
External references
- oeis: A321867