A227950 Number of decimal digits in the increasing sequence of primes obtainable by concatenating successive decrements from some power of 10.
3, 5, 5, 7, 9, 11, 13, 13, 15, 17, 19, 21, 25, 27, 53, 81, 85, 183, 191, 307, 377, 409, 475, 541, 565, 885, 1065, 1399, 1489, 2653, 4523, 4565, 5773, 7777, 14281
Offset: 1
Examples
1000999998997 is one of the primes described and provides a value of 13 in this sequence, with 1000000999999 providing the other (A227949(7) and A227949(8), in opposite order for the purposes of the FORMULA at that sequence (technically)).