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

1,1

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, ...}.

Links

Table of n, a(n) for n=1..6.

Mathematica

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

Crossrefs

Cf. A123704, A121877.

Sequence in context: A253166 A236948 A184216 * A237364 A371865 A251498

Adjacent sequences: A123702 A123703 A123704 * A123706 A123707 A123708

Keyword

nonn

Author

Alexander Adamchuk, Oct 08 2006

Status

approved