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%I #14 Apr 30 2014 01:34:07
%S 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,
%T 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,
%U 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
%N Decimal expansion of Sum_{k>0} -(-1)^k / k!^(1/k).
%C Very slow convergence!
%p 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);
%t 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 *)
%o (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 */
%K cons,nonn
%O 0,1
%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Feb 14 2008
%E Definition corrected by _Michael Somos_, Mar 01 2008
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