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A110071 Numbers n such that n=pi(d_1!!*d_2!!*...*d_k!!) where d_1 d_2 ... d_k is the decimal expansion of n. 2
0, 4, 290, 11387, 1656281 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

There is no further term up to 73*10^6. - Farideh Firoozbakht, Dec 02 2007

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

11387 is in the sequence because 11387=pi(1!!*1!!*3!!*8!!*7!!).

MATHEMATICA

Do[h = IntegerDigits[n]; l = Length[h]; If[n == PrimePi[ Product[h[[k]]!!, {k, l}]], Print[n]], {n, 0, 50000}]

CROSSREFS

Cf. A097655, A110070, A110072.

Sequence in context: A110816 A112322 A281535 * A256703 A176432 A278924

Adjacent sequences:  A110068 A110069 A110070 * A110072 A110073 A110074

KEYWORD

base,hard,more,nonn

AUTHOR

Farideh Firoozbakht, Jul 22 2005

EXTENSIONS

1656281 added by Farideh Firoozbakht, Dec 02 2007

STATUS

approved

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Last modified November 14 06:14 EST 2018. Contains 317162 sequences. (Running on oeis4.)