A143086 Triangle read by rows: T(n,k) = 2^(k + 1) - 1 if k < = floor(n/2), otherwise 2^(n - k + 1) - 1, for 0 <= k <= n.

1, 1, 1, 1, 3, 1, 1, 3, 3, 1, 1, 3, 7, 3, 1, 1, 3, 7, 7, 3, 1, 1, 3, 7, 15, 7, 3, 1, 1, 3, 7, 15, 15, 7, 3, 1, 1, 3, 7, 15, 31, 15, 7, 3, 1, 1, 3, 7, 15, 31, 31, 15, 7, 3, 1, 1, 3, 7, 15, 31, 63, 31, 15, 7, 3, 1, 1, 3, 7, 15, 31, 63, 63, 31, 15, 7, 3, 1, 1, 3, 7, 15, 31, 63, 127, 63, 31, 15, 7, 3, 1

Offset

0,5

Links

Table of n, a(n) for n=0..90.

Example

{1},
{1,  1},
{1,  3,  1},
{1,  3,  3,  1},
{1,  3,  7,  3,  1},
{1,  3,  7,  7,  3,  1},
{1,  3,  7, 15,  7,  3,  1},
{1,  3,  7, 15, 15,  7,  3,  1},
{1,  3,  7, 15, 31, 15,  7,  3,  1},
{1,  3,  7, 15, 31, 31, 15,  7,  3,  1},
{1,  3,  7, 15, 31, 63, 31, 15,  7,  3,  1}

Mathematica

Table[Table[If[m < = Floor[n/2], 2^(m + 1) - 1, 2^(n - m + 1) - 1], {m, 0, n}], {n, 0, 10}]; Flatten'%]

Crossrefs

Cf. A077866 (row sums).

Sequence in context: A123191 A157454 A106255 * A327481 A152714 A174546

Adjacent sequences: A143083 A143084 A143085 * A143087 A143088 A143089

Keyword

nonn,tabl,easy,less

Author

Roger L. Bagula and Gary W. Adamson, Oct 16 2008

Extensions

Offset changed to 0 by Georg Fischer, Jun 08 2023

Status

approved