A001520a(n) = (6*n+1)*(6*n+3)*(6*n+5).

15, 693, 3315, 9177, 19575, 35805, 59163, 90945, 132447, 184965, 249795, 328233, 421575, 531117, 658155, 803985, …

The first 2 terms appear at position 113,221.

…43248996307701137134467515693024488548207712413355773…
position 113,221
termsstringfirst positionoccurrences
115310,001,496
215693113,22110,015
3156933315not within 1,000,000,0000

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