OFFSET
1,2
COMMENTS
Consider an extension of exp(x) to an intriguing function, expim(x,y), defined by the power series Sum_{n=0..inf}(x^n/c_n), where c_0 = 1, c_n = c_(n-1)*(n+y*I), so that exp(x) = expim(x,0). The current sequence regards the absolute value of expim(1,1). The decimal expansions of the real and imaginary parts of expim(1,1) are in A231532 and A231533, respectively.
LINKS
Stanislav Sykora, Table of n, a(n) for n = 1..10000
EXAMPLE
1.8426202983147305389585438...
PROG
(PARI) Expim(x, y)={local (c, k, lastval, val); c = 1.0+0.0*I; lastval = c; k = 1; while (k, c*=x/(k + y*I); val = lastval + c; if (val==lastval, break); lastval = val; k += 1; ); return (val); }
abs(Expim(1, 1))
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Stanislav Sykora, Nov 10 2013
STATUS
approved