My dear Frenchman...............complete with 5 and 10s................4 's and 6's......................come again...........but I am making this up.........two 13s..............1st 25 primes.......1 + 25 = 26..........13 + 13 = 26.............13 primes starting with 2..............and taking every other...........like every other neg integer has a zero...............even integers..........like 2pi.............like using 2 as a simple sieve.......it would cut out......half ........1/2 of the entire number line.........above it from being prime........the trivial zeroes............are not so trivial...............

Patterns Within the Triangle

Diagonals

The first diagonal is, of course, just "1"s
The next diagonal has the Counting Numbers (1,2,3, etc).
The third diagonal has the triangular numbers
(The fourth diagonal, not highlighted, has the tetrahedral numbers.)

Symmetrical

The triangle is also symmetrical. The numbers on the left side have identical matching numbers on the right side, like a mirror image.