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 A092632 Nonprime numbers with exactly two nonprime digits. 0
 10, 14, 16, 18, 40, 44, 46, 48, 49, 60, 64, 66, 68, 69, 80, 81, 84, 86, 88, 90, 91, 94, 96, 98, 99, 102, 105, 112, 115, 117, 120, 121, 124, 126, 128, 129, 130, 134, 136, 138, 142, 143, 145, 147, 150, 154, 156, 158, 159, 162, 165, 170, 171, 174, 176, 178, 182, 183 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 10 is nonprime and has two nonprime digits, 0 and 1; 963 is nonprime and has two nonprime digits, 6 and 9. 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_neprnd:=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) = 2) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_nepr_neprnd(1000); MATHEMATICA npd2Q[n_]:=Count[IntegerDigits[n], _?(!PrimeQ[#]&)]==2; With[{nn=200}, Select[Complement[Range[nn], Prime[Range[PrimePi[nn]]]], npd2Q]] (* Harvey P. Dale, Feb 05 2012 *) CROSSREFS Sequence in context: A162708 A330210 A067188 * A213310 A055197 A116610 Adjacent sequences:  A092629 A092630 A092631 * A092633 A092634 A092635 KEYWORD nonn,base AUTHOR Jani Melik, Apr 11 2004 STATUS approved

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Last modified April 7 04:20 EDT 2020. Contains 333292 sequences. (Running on oeis4.)