A107121 Numbers m such that m=prime(prime(d_1*d_2*...*d_k)) where d_1 d_2 ... d_k is the decimal expansion of m.

461, 264961, 9548491, 14738827

Offset: 1

Author

Farideh Firoozbakht, May 13 2005

Keywords

• base
• fini
• nonn
• more

Comments

If m is in the sequence then pi(m) = prime(d_1*d_2*...*d_k) where d_1 d_2 ... d_k is the decimal expansion of m, so this sequence is a subsequence of A107120.

The sequence is finite as m >= 10^(k-1) grows faster than prime(prime(9^k)) >= prime(prime(d_1*d_2*...*d_k)). If it exists, a(5) > 10^14. - Max Alekseyev, Dec 30 2024

Examples

			14738827 is in the sequence because 14738827=prime(prime(1*4*7*3*8*8*2*7)).
		

Crossrefs

Cf. A097223, A107120, A107122.

Programs

Mathematica

Do[h= IntegerDigits[Prime[m]];l = Length[h];If[Min[h] > 0 && m == Prime[Product[h[[k]], {k, l}]], Print[Prime [m]]], {m, 20000000}]