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.

0, 4, 290, 11387, 1656281

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