A028275 Elements in 4-Pascal triangle (by row).

1, 1, 1, 1, 4, 1, 1, 5, 5, 1, 1, 6, 10, 6, 1, 1, 7, 16, 16, 7, 1, 1, 8, 23, 32, 23, 8, 1, 1, 9, 31, 55, 55, 31, 9, 1, 1, 10, 40, 86, 110, 86, 40, 10, 1, 1, 11, 50, 126, 196, 196, 126, 50, 11, 1, 1, 12, 61, 176, 322, 392, 322, 176, 61, 12, 1, 1, 13, 73, 237, 498, 714, 714, 498, 237

Offset

0,5

Links

Table of n, a(n) for n=0..74.

Formula

Apart from first 3 rows, use the Pascal rule.

T(n, k) = C(n, k) + 2C(n-2, k-1). G.f.: (1+2x^2y) / [1-x(1+y)]. - Ralf Stephan, Jan 31 2005

Example

1; 1 1; 1 4 1; 1 5 5 1; 1 6 10 6 1; ...

Crossrefs

Cf. A028262, A028313.

Sequence in context: A318795 A099575 A173740 * A173118 A147289 A147566

Adjacent sequences: A028272 A028273 A028274 * A028276 A028277 A028278

Keyword

easy,nonn

Author

Mohammad K. Azarian

Extensions

More terms from Ben Baugher (s1191623(AT)cedarville.edu)

Status

approved