A139396 - OEIS

A139396

Decimal expansion of the alternating sum 1/p(1) + 1/(p(2)*p(3)) - 1/(p(4)*p(5)*p(6)) + 1/(p(7)*p(8)*p(9)*p(10)) - ..., where p(n) is the n-th prime.

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

(list; constant; graph; refs; listen; history; text; internal format)

OFFSET

0,1

COMMENTS

Absolute difference between this number and A139395 is about 0.002.

LINKS

Table of n, a(n) for n=0..99.

EXAMPLE

0.565672296803061897703842486975162763257208610722803220614...

MAPLE

P:=proc(n) local a, b, i, j, k; a:=0.5; k:=1; for i from 2 by 1 to n do b:=1; for j from k by 1 to k+i-1 do b:=b*1/ithprime(j+1); od; k:=j; a:=evalf(a+b*(-1)^i, 105); od; print(a); end: P(100);

CROSSREFS

Cf. A139395.

Sequence in context: A006944 A010717 A046603 * A010487 A177957 A223171

Adjacent sequences: A139393 A139394 A139395 * A139397 A139398 A139399

KEYWORD

nonn,easy,cons

AUTHOR

Paolo P. Lava and Giorgio Balzarotti, Apr 18 2008

EXTENSIONS

Definition corrected by Bruno Berselli, Feb 27 2014

STATUS

approved