A092629 Numbers that have a nonprime number of prime digits.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 24, 26, 28, 29, 30, 31, 34, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 54, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 74, 76, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88

Offset

1,2

Links

Table of n, a(n) for n=1..72.

Example

24 has one prime digit 2 and their number 1 is nonprime;
235719 has four prime digits 2,3,5,7 and their number 4 is nonprime.
313 is not in the sequence as it has a prime number (2) of prime digits (3, 3). - David A. Corneth, Aug 09 2023

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_stpf:=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))='true') then stpf:=stpf+1; # number of prime digits fi od; RETURN(stpf) end: ts_nepr:=proc(n) local i, stpf, ans, ans1; ans:=[ ]: stpf:=0: for i from 1 to n do if (isprime( ts_stpf(i) )='false') then ans:=[ op(ans), i ]: fi od; RETURN(ans) end: ts_nepr(600);

Mathematica

Select[Range[100], !PrimeQ[Count[IntegerDigits[#], _?PrimeQ]]&] (* Harvey P. Dale, Jan 15 2013 *)

Crossrefs

Cf. A019546.

Sequence in context: A162421 A275164 A076499 * A246101 A241673 A258009

Adjacent sequences: A092626 A092627 A092628 * A092630 A092631 A092632

Keyword

nonn,easy,base

Author

Jani Melik, Apr 11 2004

Extensions

Edited by Charles R Greathouse IV, Aug 03 2010

Status

approved