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Search: id:A092623
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| A092623 |
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Primes with three prime digits. |
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+0
1
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| 223, 227, 233, 257, 277, 337, 353, 373, 523, 557, 577, 727, 733, 757, 773, 1223, 1237, 1277, 1327, 1373, 1523, 1553, 1723, 1733, 1753, 1777, 2027, 2053, 2137, 2153, 2203, 2207, 2213, 2221, 2239, 2243, 2251, 2267, 2287, 2293, 2297, 2339, 2347, 2351, 2371
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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223 is prime and it has three prime digits 2,2,3;
1237 is prime and it has three prime digits 2,3,7;
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MAPLE
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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_pr_prnt:=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_stpf(i) = 3) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_prnt(5000);
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CROSSREFS
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Cf. A034844, A019546.
Sequence in context: A043499 A105982 A100607 this_sequence A098591 A142386 A102950
Adjacent sequences: A092620 A092621 A092622 this_sequence A092624 A092625 A092626
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KEYWORD
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nonn
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AUTHOR
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Jani Melik (jani_melik(AT)hotmail.com), Apr 11 2004
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