A135871 Triangle by columns: A013610 signed and interleaved with zeros.

1, 0, 3, -1, 0, 9, 0, -6, 0, 27, 1, 0, -27, 0, 81, 0, 9, 0, -108, 0, 243, -1, 0, 54, 0, -405, 0, 729, 0, -12, 0, 270, 0, -1458, 0, 2187

Offset

1,3

Comments

Row sums = even-indexed Fibonacci numbers, A001906: (1, 3, 8, 21, 55, ...) such that the sum of n-th row terms = F(2n). Example: sum of nonzero terms of row 4 = (-6 + 27) = 21 = F(8).

Links

Table of n, a(n) for n=1..36.

Formula

The triangle starts with A013610, then by columns sign (+, -, +, ...) and interleave with zeros.

Example

First few rows of the triangle:
   1;
   0,  3;
  -1,  0,   9;
   0, -6,   0,   27;
   1,  0, -27,    0,   81;
   0,  9,   0, -108,    0, 243;
  -1,  0,  54,    0, -405,   0, 729;
  ...

Crossrefs

Cf. A013610, A001906.

Sequence in context: A078521 A194938 A299614 * A126178 A094753 A355350

Adjacent sequences: A135868 A135869 A135870 * A135872 A135873 A135874

Keyword

tabl,sign

Author

Gary W. Adamson, Dec 02 2007

Status

approved