A092628 Primes with exactly three nonprime digits.

101, 109, 149, 181, 191, 199, 401, 409, 419, 449, 461, 491, 499, 601, 619, 641, 661, 691, 809, 811, 881, 911, 919, 941, 991, 1013, 1021, 1031, 1039, 1051, 1063, 1087, 1093, 1097, 1103, 1117, 1129, 1151, 1163, 1171, 1187, 1193, 1201, 1249, 1289, 1291

Offset: 1

Author

Jani Melik, Apr 11 2004

Keywords

• nonn
• base

Examples

			101 is prime and it has three nonprime digits, 0 and twice 1;
4261 is prime and it has three nonprime digits, 1, 4 and 6.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A019546, A034844.

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_neprnt:=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) = 3) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_neprnt(5000);

Mathematica

dgQ[n_]:=Count[IntegerDigits[n],?(!PrimeQ[#]&)]==3; Select[Prime[ Range[300]], dgQ] (* _Harvey P. Dale, Oct 11 2011 *)