A076696 Triangle read by rows: n-th row contains n numbers whose product is a square; all numbers in triangle are distinct.

1, 2, 8, 3, 7, 21, 4, 5, 6, 30, 9, 10, 12, 15, 18

Offset

1,2

Comments

Second solution. Both solutions are smaller than A076031.

Links

Table of n, a(n) for n=1..15.

Johann Cigler, Weights of bounded Dyck paths which are related to q-Narayana polynomials, ResearchGate, Univ. Vienna (Austria 2026). See p. 12.

Example

1^2 4^2 21^2 60^2 540^2 = (1)(2 8)(3 7 21)(4 5 6 30)(9 10 12 15 18)

Crossrefs

Cf. A076031, A076596.

Sequence in context: A190732 A081349 A111445 * A391666 A011057 A082236

Adjacent sequences: A076693 A076694 A076695 * A076697 A076698 A076699

Keyword

more,nonn,tabl,obsc,changed

Author

Donald S. McDonald, Nov 10 2002

Extensions

It is not clear to me how one decides what numbers to place in the n-th row! - N. J. A. Sloane, Nov 30 2002

Status

approved