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A092620 Numbers with exactly one prime digit. 7
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A193238(a(n))=1; subsequence of A118950. [Reinhard Zumkeller, Jul 19 2011]

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

12 has one prime digit, 2;

102 has one prime digit, 2.

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_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);

PROG

(Haskell)

import Data.List (elemIndices)

a092620 n = a092620_list !! (n-1)

a092620_list = elemIndices 1 a193238_list

-- Reinhard Zumkeller, Jul 19 2011

CROSSREFS

Cf. A046034, A084984, A092624, A092625.

Sequence in context: A116692 A114983 A118950 * A028843 A028842 A140971

Adjacent sequences:  A092617 A092618 A092619 * A092621 A092622 A092623

KEYWORD

nonn,base

AUTHOR

Jani Melik, Apr 11 2004

STATUS

approved

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Last modified December 20 00:41 EST 2014. Contains 252240 sequences.