A079530a(n) = phi(n) - ceiling(sqrt(n)).

0, -1, 0, 0, 1, -1, 3, 1, 3, 0, 6, 0, 8, 2, 4, 4, …

This sequence has negative terms. Minus signs are dropped before searching.

The first 6 terms appear at position 3,137,802.

…688363948806709184862640010011933208067513131005962607…
position 3,137,802
termsstringfirst positionoccurrences
103299,993,942
2011679,998,250
3010853998,884
40100853100,044
501001292,0979,880
60100113,137,802976
701001138,265,987105
801001131181,484,69014
9010011313181,484,6905
100100113130293,103,5751
1101001131306293,103,5751
12010011313060293,103,5751

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