A176426 Decimal expansion of the product 1/(1 - 1/A000668(n)^2), n= 1 to infinity.

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

Offset

1,3

Links

Table of n, a(n) for n=1..101.

Example

equals 1.149705...

Mathematica

(*A000668 Mersenne primes *);
$MaxExtraPrecision = 200;
a = Flatten[Table[If[PrimeQ[2^n - 1], 2^n - 1, {}], {n, 0, 2000}]];
c = N[Product[1/(1 - 1/a[[n]]^2), {n, 1, Length[a]}], 100];
Table[Mod[Floor[10^n*c], 10], {n, 0, 100}]

Crossrefs

Cf. A000668

Sequence in context: A109987 A021672 A278810 * A114720 A053511 A216676

Adjacent sequences: A176423 A176424 A176425 * A176427 A176428 A176429

Keyword

nonn,cons

Author

Roger L. Bagula, Apr 17 2010

Extensions

Invalid claim concerning A065443 removed, keyword:cons inserted, offset corrected - The Assoc. Eds. of the OEIS, Apr 23 2010

Status

approved