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A298012
a(0)=a(1)=0; thereafter a(n) = A162973(n)/(n-1).
0
0, 0, 1, 1, 4, 16, 85, 533, 3888, 32268, 300193, 3093377, 34970468, 430293488, 5724411845, 81871668773, 1252691817856, 20417647146396, 353169795861921, 6461418976274657, 124664729763630436
OFFSET
0,5
LINKS
John Riordan, Letter to N. J. A. Sloane, Sep 26 1980 with notes on the 1973 Handbook of Integer Sequences. Note that the sequences are identified by their N-numbers, not their A-numbers.
FORMULA
Riordan gives a recurrence.
CROSSREFS
Sequence in context: A125793 A121145 A144882 * A006681 A074876 A238722
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 10 2018
STATUS
approved