In OEIS A008284 there is a triangular array of numbers, is the description for the formula saying that the triangular array is formed in a way similar to Pascal's triangle or is the sequence simply formed into a triangle after its created?
Triangular array or a sequence organised into a triangular array?
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sequences-and-series
1 Answers
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As with many such triangular arrays in the OEIS the triangle is naturally formed from a doubly indexed sequence of numbers such as $T(n,k)$ where $1\le k\le n$ or something similar where the lower bound is $0$ instead of $1$. In some other cases there is a doubly indexed array of numbers such as $A(i,j)$ where $1\le i$ and $1\le j$ and the elements of the array are read by anti-diagonals going up or down. There are a few more special cases, such as a sequence that makes sense as a linear array of numbers but also if arranged in a triangle. Famously, the OEIS sequence A010054 related to triangular numbers.