A223657Number of 7Xn 0..1 arrays with all rows having a nonnegative second derivative, and all and columns having a positive second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative.
60, 3600, 10425, 1059839, 24559913, 1119629805, 47882329200, 2061491256869, 95329202955957, 6980023496929171, 335311367775542739, 17119067750905601475, 1054799368422675063804, 74856492204365399292957
The first 2 terms appear at position 34,548.
…14808651328230664709384460955058223172535940812848…
…146146616794040905186152603600925219472188909181073358…
| terms | string | first position | occurrences |
|---|---|---|---|
| 1 | 60 | 127 | 10,002,175 |
| 2 | 603600 | 34,548 | 1,001 |
| 3 | 60360010425 | not within 1,000,000,000 | 0 |
Searched the first 1,000,000,000 digits. Strings longer than 12 digits are not indexed.