This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
First few rows of the triangle: 1; 2, 1; 4, 3, 1; 7, 6, 3, 1; 12, 11, 7, 3, 1; 20, 19, 14, 7, 3, 1; 33, 32, 26, 15, 7, 3, 1; ...
a(4) = 15 = sum of row 4, triangle A131411; (3 + 3 + 4 + 5).
F:=Fibonacci;; List([1..40], n-> F(n+2)+n*F(n)-(n+1)); # G. C. Greubel, Jul 13 2019
F:=Fibonacci; [F(n+2)+n*F(n)-(n+1): n in [1..40]]; // G. C. Greubel, Jul 13 2019
With[{F=Fibonacci}, Table[F[n+2]+n*F[n]-(n+1), {n,40}]] (* G. C. Greubel, Jul 13 2019 *)
a(n) = n*(fibonacci(n) - 1) + fibonacci(n+2) - 1; \\ Andrew Howroyd, Aug 10 2018
Vec((1 - 2*x + 3*x^2 - 3*x^3)/((1 - x)^2*(1 - x - x^2)^2) + O(x^40)) \\ Andrew Howroyd, Aug 10 2018
f=fibonacci; [f(n+2)+n*f(n)-(n+1) for n in (1..40)] # G. C. Greubel, Jul 13 2019
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