A097223 Prime numbers p such that p = prime(n) and n = product of the digits of p.

17, 73, 2475989

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