cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A099756 For each single digit {0,1,...,9} record the smallest prime made up of copies of that digit (if there is one); repeat for all of the C(10,2) = 45 pairs of distinct decimal digits; then for all triples; etc.

Original entry on oeis.org

11, 2, 3, 5, 7, 101, 211, 13, 41, 151, 61, 17, 181, 19, 23, 227, 29, 43, 53, 37, 83, 47, 449, 557, 59, 67, 787, 79, 89, 1021, 103, 401, 1051, 601, 107, 1801, 109, 2003, 2027, 2029, 4003, 503, 307, 3083, 4007, 409, 5077, 509, 607, 8087, 709, 809, 1123, 241, 251, 1621
Offset: 1

Views

Author

N. J. A. Sloane, Nov 11 2004

Keywords

Examples

			There are no primes that consist of copies of the digit 4, or 6, or 8, or 9, or {0,2}, or {0,3}, ..., {0,2,4,5,6,8}.
		

Crossrefs

Inspired by A099651. Cf. A016112.

Programs

  • Mathematica
    ss = Subsets[Range[0, 9], 10]; dlt =  {1, 2, 6, 8, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 30, 31, 32, 34, 38, 41, 42, 43, 45, 47, 49, 52, 53, 66, 67, 68, 70, 74, 77, 78, 79, 81, 83, 85, 88, 89, 127, 128, 130, 132, 134, 137, 153, 157, 159, 162, 168, 211, 212, 214, 216, 218, 221, 237, 241, 243, 246, 252, 332, 334, 337, 343, 373, 458, 460, 463, 469, 499, 604, 730}; ss = Delete[ss, {#} & /@ dlt]; k = 1; lst = {}; f[n_] := Block[{id = ss[[n]], p = NextPrime[ NestWhileList[ Quotient[#, 10] &, FromDigits[ss[[n]]], # > 0 &][[-2]]*10^(Length[ ss[[n]]] - If[ Mod[ FromDigits@ ss[[n]], 3] == 0, 0, 1]) - 1]}, While[ Union@ IntegerDigits@ p != id, p = NextPrime@ p]; p]; f[3] = 3; Array[ f, 950] (* Robert G. Wilson v, Apr 06 2024 *)

Extensions

More terms from Labos Elemer, Nov 15 2004