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A108934
Triangle obtained by considering certain successive approximations to the Bell numbers.
0
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
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
KEYWORD
easy,nonn,tabl
AUTHOR
Paul Boddington, Jul 20 2005
STATUS
approved