A037054 a(n)-th prime is the smallest prime containing exactly n 1's.

1, 6, 5, 187, 1242, 9682, 86538, 733339, 5821735, 56196114, 503193257, 4161915701, 41621368333, 383118399789, 3549047966306, 33056584174792, 309353882119895, 2651938403956789, 27417323062119921, 27417323062119920, 2461813897281353902, 23422580231698331842

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, A037055, A034388.

Cf. A037052, A037056, A037058, A037060, A037062, A037064, A037066, A037068, A037070.

Programs

Mathematica

(* see A037055 for f *) PrimePi[ Table[ f[n, 1], {n, 1, 13}]]

Formula

a(n) = A000720(A037055(n)). - Amiram Eldar, Jul 20 2025

Extensions

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

a(14)-a(21) calculated using Kim Walisch's primecount and added by Amiram Eldar, Jul 20 2025