A092730 Denominators in an expansion for sqrt(2).

2, 11, 780, 180120, 602397129892, 1056102638179040007288663, 327737656399044928534482808981921590582331458173

Offset

1,1

Comments

Denominators of an alternating series for sqrt(2) where the n-th numerator is the n-th digit of Pi, see example. - Michel Marcus, Aug 03 2013

Links

Table of n, a(n) for n=1..7.

Example

Sqrt(2) = 3/2 + (-1)/11 + 4/780 + (-1)/180120 + 5/602397129892 + (-9)/1056102638179040007288663 + ... with successive digits of Pi as numerators.

Prog

(PARI) a(nn) = {vpi = digits(floor(Pi*10^(nn-1)), 10); val = 0; isign = 1; for (i=1, #vpi, ai = floor((isign*vpi[i])/(sqrt(2)-val)); print1(ai, ", "); val += isign * vpi[i]/ai; isign *= -1; ); } \\ Michel Marcus, Aug 01 2013

Crossrefs

Cf. A002193.

Sequence in context: A128855 A262547 A206846 * A157841 A293240 A365098

Adjacent sequences: A092727 A092728 A092729 * A092731 A092732 A092733

Keyword

nonn,base

Author

Yalcin Aktar, Apr 12 2004, Feb 22 2007

Status

approved