A100106 Decimal expansion of Sum_{k>0} -(-1)^k / k!^(1/k).

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

Offset

0,1

Comments

Very slow convergence!

Links

Table of n, a(n) for n=0..104.

Maple

P:=proc(n) local a, i; a:=0; for i from 1 by 1 to n do a:=evalf(a+(-1)^(i-1)/((i!)^(1/i)), 50); print(a); od; end: P(100000);

Mathematica

digits = 105; NSum[-(-1)^k/k!^(1/k), {k, 1, Infinity}, Method -> "AlternatingSigns", WorkingPrecision -> digits+10] // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Feb 18 2014 *)

Prog

(PARI) {a(n) = if( n<0, 0, n++; default( realprecision, n+2); floor( sumalt( k=1, -(-1)^k / k!^(1/k)) * 10^n) % 10)} /* Michael Somos, Jan 17 2012 */

Crossrefs

Sequence in context: A021630 A079459 A118309 * A349161 A125650 A171540

Adjacent sequences: A100103 A100104 A100105 * A100107 A100108 A100109

Keyword

cons,nonn

Author

Paolo P. Lava and Giorgio Balzarotti, Feb 14 2008

Extensions

Definition corrected by Michael Somos, Mar 01 2008

Status

approved