

A139687


Basis of degenerate cases of sequences identical to its pth differences. Complement to A140344 which is based on natural Catalan's triangle. Triangle without first term (probable 1) on line.


3



1, 1, 1, 2, 2, 1, 3, 5, 5, 1, 3, 6, 9, 9, 1, 4, 10, 19, 28, 28, 1, 4, 10, 20, 34, 48, 48, 1, 5, 15, 35, 69, 117, 165, 165, 1, 5, 15, 35, 70, 125, 200, 275, 275, 1, 6, 21, 56, 126, 251, 451, 726, 1001, 1001, 1, 6, 21, 56, 126, 252, 461, 780, 1209, 1638, 1638
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OFFSET

0,4


COMMENTS

Triangle from A140344:
(1;)
0, 1, 1;
0, 0, 1, 2, 2;
0, 0, 0, 1, 3, 5, 5; see A138112,
0, 0, 0, 0, 1, 4, 9, 14, 14; see A140343,
begins (without 0's) like a(n).


LINKS

Table of n, a(n) for n=0..64.


FORMULA

First four rows of triangle from second row: 1, 1; 1, 2, 2; see A099087, 1, 3, 5, 5; 1, 3, 6, 9, 9; see A057083 which can be preceded with 3 leading 0's, are, as said, from natural Catalan's triangle A009766. Origin of a(n) explained later.


CROSSREFS

Cf. A135356.
Sequence in context: A303911 A205575 A257006 * A188181 A064581 A064580
Adjacent sequences: A139684 A139685 A139686 * A139688 A139689 A139690


KEYWORD

nonn,uned


AUTHOR

Paul Curtz, Jun 13 2008


STATUS

approved



