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A107121 Numbers n such that n=prime(prime(d_1*d_2*...*d_k)) where d_1 d_2 ... d_k is the decimal expansion of n. 2
461, 264961, 9548491, 14738827 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If n is in the sequence then pi(n) = prime(d_1*d_2* ...d_k) where d_1 d_2 ... d_k is the decimal expansion of n, so this sequence is a subsequence of A107120. There is no further term up to prime(2*10^7).

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

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

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}]

CROSSREFS

Cf. A097223, A107120, A107122.

Sequence in context: A142832 A277989 A138956 * A101734 A059025 A267200

Adjacent sequences:  A107118 A107119 A107120 * A107122 A107123 A107124

KEYWORD

base,nonn

AUTHOR

Farideh Firoozbakht, May 13 2005

STATUS

approved

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Last modified October 21 01:18 EDT 2019. Contains 328291 sequences. (Running on oeis4.)