
COMMENTS

Start with decimal expansion of Pi: 3,1,4,1,5,9,2,6,5,3,5,8,9,7,9,3,2,3,8,4,6,2,6,4,3... Part the sequence to the sections with distinct digits: s={3,1,4},{1,5,9,2,6},{5,3},{5,8,9,7},{9,3,2},{3,8,4,6,2},{6,4,3},... Then A104819(n) = number from digits of s(n): 314,15926,53,5897,932,38462,643,... Leading zero allowed as at first in a(42)= 193852 from {0,1,9,3,8,5,2}.
