A092630 Nonprime numbers with exactly one nonprime digit.

1, 4, 6, 8, 9, 12, 15, 20, 21, 24, 26, 28, 30, 34, 36, 38, 39, 42, 45, 50, 51, 54, 56, 58, 62, 63, 65, 70, 74, 76, 78, 82, 85, 87, 92, 93, 95, 122, 123, 125, 132, 133, 135, 152, 153, 155, 172, 175, 177, 202, 203, 205, 207, 212, 213, 215, 217, 220, 221, 224, 226, 228

Offset

1,2

Links

Table of n, a(n) for n=1..62.

Example

20 is nonprime and has one nonprime digit, 0;
122 is nonprime and has one nonprime digit, 1.

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_nepr_neprn:=proc(n) local i, stpf, ans, ans1, tren; ans:=[ ]: stpf:=0: tren:=1: for i from 1 to n do if ( isprime(i)='false' and ts_stnepf(i) = 1) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_nepr_neprn(1000);

Crossrefs

Sequence in context: A067012 A157942 A122786 * A079142 A062002 A090419

Adjacent sequences: A092627 A092628 A092629 * A092631 A092632 A092633

Keyword

nonn,base

Author

Jani Melik, Apr 11 2004

Status

approved