

A080382


Triangle read by rows: C[n,Floor[n/2]]/GCD[C[n,Floor[n/2]],C[n,i], i=0,...n; central binomial coefficient is divided by greatest common divisor of binomial coefficients and corresponding central binomial coefficient.


0



1, 1, 1, 2, 1, 2, 3, 1, 1, 3, 6, 3, 1, 3, 6, 10, 2, 1, 1, 2, 10, 20, 10, 4, 1, 4, 10, 20, 35, 5, 5, 1, 1, 5, 5, 35, 70, 35, 5, 5, 1, 5, 5, 35, 70, 126, 14, 7, 3, 1, 1, 3, 7, 14, 126, 252, 126, 28, 21, 6, 1, 6, 21, 28, 126, 252, 462, 42, 42, 14, 7, 1, 1, 7, 14, 42, 42, 462, 924, 77, 14, 21, 28
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OFFSET

1,4


LINKS

Table of n, a(n) for n=1..83.


EXAMPLE

Triangle begins:
1
1 1
2 1 2
3 1 1 3
6 3 1 3 6
10 2 1 1 2 10
20 10 4 1 4 10 20
35 5 5 1 1 5 5 35


MATHEMATICA

Table[Table[Binomial[n, Floor[n/2]]/GCD[Binomial[n, j], Binomial[n, Floor[n/2]]], {j, 0, n}], {n, 1, 10}]


CROSSREFS

Cf. A007318, A001405, A080381.
Sequence in context: A109004 A103823 A136642 * A106394 A171712 A091412
Adjacent sequences: A080379 A080380 A080381 * A080383 A080384 A080385


KEYWORD

nonn,tabl


AUTHOR

Labos Elemer, Mar 12 2003


STATUS

approved



