A386949 Irregular triangle whose n-th row lists the nonzero terms of the n-th column of A386755.

1, 1, 2, 2, 1, 3, 3, 3, 3, 1, 2, 2, 4, 4, 1, 5, 5, 5, 5, 5, 5, 1, 2, 2, 3, 3, 6, 6, 6, 6, 1, 7, 7, 7, 7, 7, 7, 7, 7, 1, 2, 2, 4, 4, 4, 4, 4, 4, 8, 8, 8, 8, 1, 3, 3, 3, 3, 9, 9, 9, 9, 9, 9, 9, 9, 1, 2, 2, 5, 5, 5, 5, 10, 10, 10, 10, 10, 10, 1, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11

Offset

1,3

Links

Table of n, a(n) for n=1..89.

Example

Triangle begins:
  1;
  1, 2, 2;
  1, 3, 3, 3, 3;
  1, 2, 2, 4, 4;
  1, 5, 5, 5, 5, 5, 5;
  1, 2, 2, 3, 3, 6, 6, 6, 6;
  1, 7, 7, 7, 7, 7, 7, 7, 7;
  1, 2, 2, 4, 4, 4, 4, 4, 4, 8, 8, 8, 8;
  1, 3, 3, 3, 3, 9, 9, 9, 9, 9, 9, 9, 9;
  1, 2, 2, 5, 5, 5, 5, 10, 10, 10, 10, 10, 10;
  ...

Prog

(PARI) orow(n) = my(v=vector(n), m=n); for(k=1, n, my(keepm = m); while(m%k, m--); if (m == 0, keepm=m, v[m] = k; m--); ); v; \\ A386755
nrow(n) = my(ok=1, k=1, last=-1, list=List(), r); while(ok, r=row(k); if ((#r >= n) && r[n], listput(list, r[n])); k++; if (#r>=n, if ((last==n) && (r[n]==0), ok = 0, last = r[n]))); Vec(list);

Crossrefs

Cf. A386755 (original triangle), A386520 (row sums).

Cf. A027750.

Sequence in context: A194195 A164999 A292030 * A162909 A245325 A091224

Adjacent sequences: A386946 A386947 A386948 * A386950 A386951 A386952

Keyword

nonn,tabf

Author

Michel Marcus, Aug 10 2025

Status

approved