A129125 Prune the tree structure defined in sequence A129129 yielding a new irregular table with shape sequence A027336.

1, 2, 3, 5, 6, 7, 10, 9, 11, 14, 15, 18, 13, 22, 21, 25, 30, 27, 17, 26, 33, 35, 42, 50, 45, 54, 19, 34, 39, 55, 66, 49, 70, 63, 75, 90, 81

Offset

0,2

Comments

A000041 begins 1 1 2 3 5 7 11 15 22 30 42 ... and when shifted 0 0 1 1 2 3 5 7 11 15 22 ... by subtraction yielding 1 1 1 2 3 4 6 8 11 15 20 ... shape seq A027736.

Links

Table of n, a(n) for n=0..36.

Example

The original tree begins
   1;
   2;
   3,  4;
   5,  6,  8;
   7, 10,  9, 12, 16;
  11, 14, 15, 20, 18, 24, 32;
  ...
Multiplying by four yields
   4;
   8;
  12, 16;
  20, 24, 32;
  ...
These are the values to be omitted, leaving
   1;
   2;
   3;
   5,  6;
   7, 10,  9;
  11, 14, 15, 18;
  ...

Crossrefs

Cf. A000041, A027336, A129129.

Sequence in context: A030159 A030161 A361372 * A259444 A071591 A089105

Adjacent sequences: A129122 A129123 A129124 * A129126 A129127 A129128

Keyword

more,nonn,tabf

Author

Alford Arnold, Apr 04 2007

Status

approved