OFFSET
1,3
COMMENTS
Decimal expansion of 1/11 + 1/1221 + 1/123321 + ... + 1/123456789987654321 +
1/1234567891001987654321 + 1/12345678910111101987654321 + 1/123456789101112211101987654321 + ...
0.0917362824741933725002959842982939... = [0, 10, 1, 9, 12, 4, 1, 3, 6].
Rational approximation up to the 11th decimal digit: 14649/159686.
MAPLE
with(numtheory): T:=proc(w) local x, y, z; x:=w; y:=0;
for z from 1 to ilog10(x)+1 do y:=y*10+(x mod 10); x:=trunc(x/10); od; y: end:
P:=proc(q) local a, b, n; a:=0; b:=0; for n from 1 to q do
a:=trunc(a/10^((ilog10(a)+1)/2))*10^(ilog10(n)+1)+n; a:=a*10^(ilog10(a)+1)+T(a);
b:=b+1/a; od; evalf(b, 500); end: P(300);
CROSSREFS
KEYWORD
AUTHOR
Paolo P. Lava, Nov 12 2014
STATUS
approved