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.

A092626 Primes with one nonprime digit.

Original entry on oeis.org

13, 17, 29, 31, 43, 47, 59, 67, 71, 79, 83, 97, 127, 137, 157, 173, 229, 239, 251, 263, 271, 283, 293, 307, 313, 317, 331, 347, 359, 367, 379, 383, 397, 433, 457, 503, 521, 547, 563, 571, 587, 593, 653, 673, 677, 739, 743, 751, 787, 797, 823, 827, 853, 857
Offset: 1

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Author

Jani Melik, Apr 11 2004

Keywords

Comments

Heuristically, there are 15/(8 log 10) * n^(log_10 4) members up to n, or about 0.814 * n^0.602.

Examples

			13 is prime and it has one nonprime digit, 1;
3259 is prime and it has one nonprime digit, 9.
		

Crossrefs

Cf. A019546.

Programs

  • Maple
    stev_sez:=proc(n) local i, tren, st, ans, anstren; ans:=[ ]: anstren:=[ ]: tren:=n: for i while (tren>0) do st:=round( 10*frac(tren/10) ): ans:=[ op(ans), st ]: tren:=trunc(tren/10): end do; for i from nops(ans) to 1 by -1 do anstren:=[ op(anstren), op(i,ans) ]; od; RETURN(anstren); end:
    ts_stnepf:=proc(n) local i, stpf, ans; ans:=stev_sez(n): stpf:=0: for i from 1 to nops(ans) do if (isprime(op(i,ans))='false') then stpf:=stpf+1; # number of nonprime digits fi od; RETURN(stpf) end:
    ts_pr_neprn:=proc(n) local i, stpf, ans, ans1, tren; ans:=[ ]: stpf:=0: tren:=1: for i from 1 to n do if ( isprime(i)='true' and ts_stnepf(i) = 1) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_neprn(4000);
  • Mathematica
    Select[Prime[Range[200]],Count[IntegerDigits[#],?(!PrimeQ[#]&)]==1&] (* _Harvey P. Dale, Feb 18 2018 *)

Extensions

Edited by R. J. Mathar, Nov 02 2009
Comment from Charles R Greathouse IV, Mar 19 2010