A037062 a(n)-th prime is the smallest prime containing exactly n 5's.

1, 3, 102, 733, 14319, 45741, 1004275, 3313338, 169807396, 259770566, 20255937351, 21366409911, 196256438549, 10949682060338, 16876678891444, 1376534319069676, 13702579963679833, 13947379867469643, 360360819534753751, 3421022095727840569, 93257415087729395138, 113268191247939457737

Offset: 0

Author

Patrick De Geest, Jan 04 1999

Keywords

• nonn
• base
• hard

Links

• Andrew R. Booker, The Nth Prime Page.
• Kim Walisch, primecount, Fast prime counting function library.

Crossrefs

Cf. A000720, A037063, A034388.

Cf. A037052, A037054, A037056, A037058, A037060, A037064, A037066, A037068, A037070.

Programs

Mathematica

(* see A037063 for f *) PrimePi[ Table[ f[n, 5], {n, 1, 12}]]

Formula

a(n) = A000720(A037063(n)). - Amiram Eldar, Jul 20 2025

Extensions

a(0)=1 prepended by Sean A. Irvine, Dec 06 2020

a(13)-a(21) calculated using Kim Walisch's primecount and added by Amiram Eldar, Jul 20 2025