A104090 Largest prime <= 5^n.

5, 23, 113, 619, 3121, 15619, 78121, 390581, 1953109, 9765619, 48828113, 244140613, 1220703073, 6103515623, 30517578121, 152587890563, 762939453109, 3814697265523, 19073486328109, 95367431640599, 476837158203071, 2384185791015571, 11920928955078089

Offset: 1

Author

Cino Hilliard, Mar 03 2005

Keywords

• easy
• nonn

Crossrefs

Cf. A014234, A054321, A104088, A104089, A104091-A104094, A003618, A104096.

Cf. A000040, A000351, A007917.

Programs

Mathematica

NextPrime[5^Range[30] + 1, -1] (* Paolo Xausa, Oct 29 2024 *)

PARI

g(n,b) = for(x=0,n,print1(precprime(b^x)","))

Formula

a(n) = A007917(A000351(n)). - Paolo Xausa, Oct 29 2024