A323641 Triangle read by rows in which row n lists the first 2^n terms of A323642, n >= 1.

1, 2, 1, 2, 3, 6, 1, 2, 3, 6, 3, 6, 9, 18, 1, 2, 3, 6, 3, 6, 9, 18, 3, 6, 9, 18, 9, 18, 27, 54, 1, 2, 3, 6, 3, 6, 9, 18, 3, 6, 9, 18, 9, 18, 27, 54, 3, 6, 9, 18, 9, 18, 27, 54, 9, 18, 27, 54, 27, 54, 81, 162, 1, 2, 3, 6, 3, 6, 9, 18, 3, 6, 9, 18, 9, 18, 27, 54, 3, 6, 9, 18, 9, 18, 27, 54, 9, 18

Offset

1,2

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Formula

a(n) = A323651(n+2)/4.

Example

Written as an irregular triangle in which the row lengths are the terms of A000079 multiplied by 2 the sequence begins:
1,2;
1,2,3,6;
1,2,3,6,3,6,9,18;
1,2,3,6,3,6,9,18,3,6,9,18,9,18,27,54;
1,2,3,6,3,6,9,18,3,6,9,18,9,18,27,54,3,6,9,18,9,18,27,54,9,18,27,54,27,54,81,162;
...
It appears that the right border gives A008776.

Mathematica

Riffle[#, 2*#]/4 & [4*3^(DigitCount[Range[50], 2, 1] - 1)] (* Paolo Xausa, Dec 18 2025 *)

Crossrefs

Cf. A000079, A008776, A139251, A147582, A323642, A323649, A323650, A323651.

Sequence in context: A277566 A261144 A106524 * A086582 A033639 A156565

Adjacent sequences: A323638 A323639 A323640 * A323642 A323643 A323644

Keyword

nonn,tabf

Author

Omar E. Pol, Mar 03 2019

Status

approved