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 A092621 Primes with exactly one prime digit. 18
 2, 3, 5, 7, 13, 17, 29, 31, 43, 47, 59, 67, 71, 79, 83, 97, 103, 107, 113, 131, 139, 151, 163, 167, 179, 193, 197, 211, 241, 269, 281, 311, 349, 389, 421, 431, 439, 443, 463, 467, 479, 487, 509, 541, 569, 599, 607, 613, 617, 631, 643, 647, 659, 683, 701, 709 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Zak Seidov, Table of n, a(n) for n = 1..10000 FORMULA a(n) >> n^1.28 because of the digit restriction EXAMPLE 13 is prime and it has one prime digit, 3; 103 is prime and it has one prime digit, 3. 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_prn:=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) = 1) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_prn(1000); MATHEMATICA podQ[n_]:=(1==Length@Select[IntegerDigits[n], PrimeQ]); Select[Prime[Range[250]], podQ](* Zak Seidov *) PROG (Sage) A092621 = list(p for p in primes(1000) if len([d for d in p.digits() if is_prime(d)]) == 1) (PARI) isok(n) = isprime(n) && (d = digits(n)) && (sum(i=1, #d, isprime(d[i])) == 1); \\ Michel Marcus, Mar 10 2014 CROSSREFS Cf. A034844, A092620. Cf. A239037 (prime digit in A092621(n)). - Zak Seidov, Mar 10 2014 Sequence in context: A001000 A094947 A231474 * A188809 A350443 A152449 Adjacent sequences: A092618 A092619 A092620 * A092622 A092623 A092624 KEYWORD nonn,base AUTHOR Jani Melik, Apr 11 2004 STATUS approved

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Last modified May 29 13:50 EDT 2024. Contains 372949 sequences. (Running on oeis4.)