A003552Divisors of 2^47 - 1.

1, 2351, 4513, 10610063, 13264529, 31184907679, 59862819377, 140737488355327

The first 2 terms appear at position 121,157.

…70247453827583966522993712351630489833012421417455788…
position 121,157
termsstringfirst positionoccurrences
11199,997,334
212351121,1579,956
3123514513not within 1,000,000,0000

Searched the first 1,000,000,000 digits. Strings longer than 12 digits are not indexed.