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A092620
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Numbers with exactly one prime digit.
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6
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2, 3, 5, 7, 12, 13, 15, 17, 20, 21, 24, 26, 28, 29, 30, 31, 34, 36, 38, 39, 42, 43, 45, 47, 50, 51, 54, 56, 58, 59, 62, 63, 65, 67, 70, 71, 74, 76, 78, 79, 82, 83, 85, 87, 92, 93, 95, 97, 102, 103, 105, 107, 112, 113, 115, 117, 120, 121, 124, 126, 128, 129, 130, 131, 134
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OFFSET
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1,1
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COMMENTS
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A193238(a(n))=1; subsequence of A118950. [Reinhard Zumkeller, Jul 19 2011]
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LINKS
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_Reinhard Zumkeller_, Table of n, a(n) for n = 1..10000
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EXAMPLE
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12 has one prime digit, 2;
102 has one prime digit, 2.
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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_n:=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) =0) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_n(300);
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PROG
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(Haskell)
import Data.List (elemIndices)
a092620 n = a092620_list !! (n-1)
a092620_list = elemIndices 1 a193238_list
-- Reinhard Zumkeller, Jul 19 2011
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CROSSREFS
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Cf. A046034, A084984, A092624, A092625.
Sequence in context: A116692 A114983 A118950 * A028843 A028842 A140971
Adjacent sequences: A092617 A092618 A092619 * A092621 A092622 A092623
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KEYWORD
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nonn,base
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AUTHOR
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Jani Melik, Apr 11 2004
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STATUS
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approved
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