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 A097223 Prime numbers p such that p = prime(n) and n = product of the digits of p. 10
 17, 73, 2475989 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence is a subsequence of A097220, so the sequence is also a subsequence of A097221. Next term if it exists is greater than 4333000000. There is no further term. [Farideh Firoozbakht, Jul 15 2009] LINKS Table of n, a(n) for n=1..3. Chris K. Caldwell and G. L. Honaker, Jr., 2475989 Carl Pomerance, What we still don't know about addition and multiplication, Trjitzinsky Lecture 1, U. Illinois Urbana-Champaign, November 27, 2018. See slides 22 & 24. EXAMPLE 2475989 is in the sequence because 2475989 is (2*4*7*5*9*8*9)-th prime. MATHEMATICA v={}; Do[If[h=IntegerDigits[Prime[n]]; l=Length[h]; p=Product[h[[k]], {k, l}]; p==n, v=Append[v, Prime[n]]; Print[v]], {n, 205000000}] PROG (PARI) isok(p) = isprime(p) && (primepi(p) == vecprod(digits(p))); \\ Michel Marcus, Jan 27 2019 CROSSREFS Cf. A097220, A097221. Sequence in context: A165691 A154419 A208399 * A296113 A231779 A063494 Adjacent sequences: A097220 A097221 A097222 * A097224 A097225 A097226 KEYWORD base,fini,full,nonn,bref AUTHOR Farideh Firoozbakht, Aug 06 2004 STATUS approved

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Last modified June 22 15:06 EDT 2024. Contains 373587 sequences. (Running on oeis4.)