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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
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. A239037 (prime digit in A092621(n)). - Zak Seidov, Mar 10 2014
Sequence in context: A001000 A094947 A231474 * A188809 A350443 A152449
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.)