A117836 Semiprimes of the form floor(e^k).

403, 3269017, 485165195, 3584912846, 26489122129, 29048849665247, 639843493530054949, 114200738981568428366295718, 66631762164108958342448140502408732626873, 492345828601205839975486205911330449483779

Offset: 1

Author

Jonathan Vos Post, Apr 30 2006

Keywords

• nonn

Examples

			a(1) = 403 = floor(e^6) = 13 * 31.
a(2) = 3269017 = floor(e^15) = 773 * 4229.
a(3) = 485165195 = floor(e^20) = 5 * 97033039.
a(4) = 3584912846 = floor(e^22) = 2 * 1792456423.
a(5) = 26489122129 = floor(e^24) = 103 * 257175943.
		

Links

• Giovanni Resta, Table of n, a(n) for n = 1..17

Crossrefs

Cf. A000040, A000149, A001358, A074496.

Programs

Mathematica

Select[Table[Floor[Exp[k]],{k,100}],PrimeOmega[#]==2&] (* James C. McMahon, Sep 14 2024 *)

Formula

A000149 Intersection A001358.

Extensions

a(6)-a(10) from Giovanni Resta, Jun 15 2016