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.
Triangle begins: n\k| 0 1 2 3 ---------------- 0 | 0; 1 | 1; 2 | 2, 1; 3 | 3, 2, 1; 4 | 4, 1; 5 | 5, 2, 1; 6 | 6, 2, 1; 7 | 7, 3, 2, 1; 8 | 8, 1; 9 | 9, 2, 1; 10 | 10, 2, 1; ...
A381962row[n_] := NestWhileList[DigitSum[#, 2] &, n, # > 1 &]; Array[A381962row, 30, 0]
def row(n):
out = [n] if n > 1 else []
while (n:=n.bit_count()) > 1:
out += [n]
return out + [n]
print([e for n in range(27) for e in row(n)]) # Michael S. Branicky, Mar 12 2025
Triangle begins: n\k| 0 1 2 --------------- 0 | 0; 1 | 1; 2 | 2; 3 | 3; 4 | 4; 5 | 5; 6 | 6; 7 | 7; 8 | 8; 9 | 9; 10 | 10, 0; 11 | 11, 1; 12 | 12, 2; 13 | 13, 3; 14 | 14, 4; 15 | 15, 5; 16 | 16, 6; 17 | 17, 7; 18 | 18, 8; 19 | 19, 9; 20 | 20, 0; 21 | 21, 2; 22 | 22, 4; 23 | 23, 6; 24 | 24, 8; 25 | 25, 10, 0; ...