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Search: id:A092625
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| A092625 |
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Numbers with three prime digits. |
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+0
1
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| 222, 223, 225, 227, 232, 233, 235, 237, 252, 253, 255, 257, 272, 273, 275, 277, 322, 323, 325, 327, 332, 333, 335, 337, 352, 353, 355, 357, 372, 373, 375, 377, 522, 523, 525, 527, 532, 533, 535, 537, 552, 553, 555, 557, 572, 573, 575, 577, 722, 723, 725
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is the same as A046034 from two digit numbers from 22 up to four digit numbers from 1222.
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EXAMPLE
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222 has three prime digits, three times 2;
1235 has three prime digits, 2, 3 and 5.
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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_nt:=proc(n) local i, stpf, ans, ans1, tren; ans:=[ ]: stpf:=0: tren:=1: for i from 1 to n do if ( ts_stpf(i) = 3) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_nt(2000);
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CROSSREFS
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Cf. A034895, A046034, A085557, A019546, A034844.
Adjacent sequences: A092622 A092623 A092624 this_sequence A092626 A092627 A092628
Sequence in context: A083959 A078212 A078251 this_sequence A043612 A101955 A063352
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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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