A110071 - OEIS

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, 538311474096

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OFFSET

1,2

COMMENTS

No other terms below 10^14. - Max Alekseyev, Jul 21 2024

LINKS

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

KEYWORD

base,hard,more,nonn

AUTHOR

EXTENSIONS

a(5) added by Farideh Firoozbakht, Dec 02 2007

a(6) from Max Alekseyev, Jul 21 2024

STATUS

approved