A108934 Triangle obtained by considering certain successive approximations to the Bell numbers.

1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 2, 1, 1, 0, 1, 4, 2, 1, 1, 0, 1, 8, 5, 2, 1, 1, 0, 1, 16, 14, 5, 2, 1, 1, 0, 1, 32, 41, 15, 5, 2, 1, 1, 0, 1, 64, 122, 51, 15, 5, 2, 1, 1, 0, 1, 128, 365, 187, 52, 15, 5, 2, 1, 1, 0, 1, 256, 1094, 715, 202, 52, 15, 5, 2, 1, 1

Offset

0,13

Links

Table of n, a(n) for n=0..77.

Formula

Each row has e.g.f. given by a truncated exponential series in exp(x)-1. For example the e.g.f. = 1 + (exp(x)-1) + (1/2)(exp(x)-1)^2 gives the sequence 1, 1, 2, 4, 8, 16... . Alternatively, first differences of columns gives triangle of Stirling numbers of 2nd kind A008277.

Example

Triangle starts:
1;
0, 1;
0, 1, 1;
0, 1, 1, 1;
0, 1, 2, 1, 1;
0, 1, 4, 2, 1, 1;
0, 1, 8, 5, 2, 1, 1;
0, 1, 16, 14, 5, 2, 1;
...

Crossrefs

Cf. A000110.

Sequence in context: A077042 A144903 A356266 * A108947 A338859 A152459

Adjacent sequences: A108931 A108932 A108933 * A108935 A108936 A108937

Keyword

easy,nonn,tabl

Author

Paul Boddington, Jul 20 2005

Status

approved