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

Offset: 1

Author

Farideh Firoozbakht, Jul 22 2005

Keywords

• base
• hard
• more
• nonn

Comments

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

Examples

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

Crossrefs

Cf. A000720, A006882, A097655, A110070, A110072.

Programs

Mathematica

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

Extensions

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

a(6) from Max Alekseyev, Jul 21 2024