

A363003


Number of integer sequences of length n whose Gilbreath transform is (1, 1, ..., 1).


5



1, 1, 2, 6, 26, 166, 1562, 21614, 438594, 13032614, 566069882
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OFFSET

0,3


COMMENTS

a(n) is even for all n >= 2, because if the sequence (x_1, ..., x_n) has Gilbreath transform (1, ..., 1), so has the sequence (2  x_1, ..., 2  x_n).
Negative terms are permitted.


LINKS



EXAMPLE

For n = 4, the following 13 sequences, together with the sequences obtained by replacing each term x by 2x in each of these sequences, have Gilbreath transform (1, 1, 1, 1), so a(4) = 26.
(1, 2, 0, 4),
(1, 2, 0, 2),
(1, 2, 0, 0),
(1, 2, 0, 2),
(1, 2, 0, 4),
(1, 2, 2, 0),
(1, 2, 2, 2),
(1, 2, 2, 4),
(1, 2, 4, 0),
(1, 2, 4, 2),
(1, 2, 4, 4),
(1, 2, 4, 6),
(1, 2, 4, 8).


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



