A123705 Primes of the form (5^p-3^p)/2, where prime p = Prime[A123704[n]] = A121877[n].

609554401, 9536162033329, 5960417405949649, 2328306127701998147089, 355271367866755685756083382145169, 29387358770557187699218413428591111182510208390715375894150039546014062887655539136439569

Offset: 1

Author

Alexander Adamchuk, Oct 08 2006

Keywords

• nonn

Comments

Corresponding primes p are listed in A121877[n] = Prime[A123704[n]] = {13, 19, 23, 31, 47, 127, 223, 281, 2083, ...} Numbers n such that (5^n-3^n)/2 is a prime. Numbers n such that (5^p-3^p)/2 is prime, where p = Prime[n], are listed in A123704[n] = {6, 8, 9, 11, 15, 31, 48, 60, 314, ...}.

Crossrefs

Cf. A123704, A121877.

Programs

Mathematica

Select[(5^#-3^#)/2&/@Prime[Range[50]],PrimeQ] (* Harvey P. Dale, Mar 30 2012 *)