A190406 - OEIS

A190406

Decimal expansion of Sum_{k>=1} (1/2)^S(k-1), where S=A001844 (centered square numbers).

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

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

OFFSET

0,1

COMMENTS

See A190404.

LINKS

Danny Rorabaugh, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = floor(10^(n+1)*Sum_{j>=0} (1/2)^(2*j*(j+1)+1)) mod 10. - Danny Rorabaugh, Mar 26 2015

MAPLE

evalf(JacobiTheta2(0, 1/4)/2^(3/2)) ; # R. J. Mathar, Jul 15 2013

MATHEMATICA