

A068913


Square array read by antidiagonals of number of k step walks (each step +/1 starting from 0) which are never more than n or less than n.


10



1, 0, 1, 0, 2, 1, 0, 2, 2, 1, 0, 4, 4, 2, 1, 0, 4, 6, 4, 2, 1, 0, 8, 12, 8, 4, 2, 1, 0, 8, 18, 14, 8, 4, 2, 1, 0, 16, 36, 28, 16, 8, 4, 2, 1, 0, 16, 54, 48, 30, 16, 8, 4, 2, 1, 0, 32, 108, 96, 60, 32, 16, 8, 4, 2, 1, 0, 32, 162, 164, 110, 62, 32, 16, 8, 4, 2, 1, 0, 64, 324, 328, 220, 124, 64, 32, 16, 8, 4, 2, 1
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OFFSET

0,5


LINKS

Alois P. Heinz, Antidiagonals n = 0..200, flattened


FORMULA

Starting with T(n, 0)=1; if (kn) is negative or even then T(n, k)=2T(n, k1); otherwise T(n, k)=2T(n, k1)A061897(n1, (kn1)/2); so for n>=k T(n, k)=2^k.


EXAMPLE

Rows start:
1,0,0,0,0,...
1,2,2,4,4,...
1,2,4,6,12,...
1,2,4,8,14,...
...


CROSSREFS

Cf. early rows: A000007, A016116 (without initial term), A068911, A068912, A216212, A216241, A235701.
Central and lower diagonals are A000079, higher diagonals include A000918, A028399.
Sequence in context: A289281 A212957 A035393 * A128306 A305152 A170983
Adjacent sequences: A068910 A068911 A068912 * A068914 A068915 A068916


KEYWORD

nonn,tabl


AUTHOR

Henry Bottomley, Mar 06 2002


STATUS

approved



