A161360 Decimal expansion of Product_p p#/(p#-1).

2, 4, 9, 5, 8, 0, 6, 5, 1, 4, 0, 5, 9, 8, 3, 8, 2, 7, 2, 7, 7, 4, 9, 7, 9, 2, 0, 4, 9, 3, 0, 1, 5, 3, 4, 3, 7, 2, 6, 1, 0, 3, 7, 9, 3, 7, 6, 1, 5, 5, 0, 7, 7, 9, 6, 3, 9, 6, 9, 1, 6, 5, 3, 8, 9, 5, 1, 3, 5, 7, 2, 2, 2, 6, 4, 9, 6, 5, 6, 5, 6, 9, 0, 4, 5, 5, 5, 7, 0, 3, 4, 8, 5, 6, 1, 3, 5, 4, 0, 0, 1, 6, 2, 5, 2

Offset

1,1

Comments

By p# we mean the primorial number which is the product of the primes less than or equal to p.

Links

Table of n, a(n) for n=1..105.

Formula

This number is equal to Sum_k 1/A025487(k).

Example

2/1 * 6/5 * 30/29 * ... = 2.495806514059838272774979204930153...

Mathematica

RealDigits[Times@@(#/(#-1)&/@Rest[FoldList[Times, 1, Prime[Range[100]]]]), 10, 120][[1]] (* Harvey P. Dale, Mar 15 2015 *)

Prog

(PARI) h(n)=local(p, pl, r); p=2; pl=1; r=1.; while(p<n, pl*=p; r/=(1-1./pl); p=nextprime(p+1)); r

Crossrefs

Cf. A002110, A034386, A025487, A064648.

Sequence in context: A301514 A377970 A269063 * A230242 A104654 A011182

Adjacent sequences: A161357 A161358 A161359 * A161361 A161362 A161363

Keyword

cons,nonn

Author

Franklin T. Adams-Watters, Jun 07 2009

Status

approved