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A186807 Triangle read by rows: T(n,p) (n >= 2, 1 <= p <= n-1) = number of compositions of n into p parts, with first part >= all other parts. 2
1, 1, 1, 1, 2, 1, 1, 3, 2, 1, 1, 4, 4, 3, 1, 1, 5, 7, 6, 3, 1, 1, 6, 11, 11, 8, 4, 1, 1, 7, 16, 19, 17, 11, 4, 1, 1, 8, 22, 31, 32, 26, 13, 5, 1, 1, 9, 29, 48, 56, 54, 35, 17, 5, 1, 1, 10, 37, 71, 93, 102, 82, 48, 20, 6, 1, 1, 11, 46, 101, 148, 180, 172, 120, 63, 24, 6, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

2,5

COMMENTS

This triangle arose in connection with a problem involving "lunar arithmetic".

Take the triangle formed by the antidiagonals of A156041 and reverse each row.

LINKS

Table of n, a(n) for n=2..79.

D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]

Index entries for sequences related to dismal (or lunar) arithmetic

EXAMPLE

Triangle begins:

1,

1, 1,

1, 2, 1,

1, 3, 2, 1,

1, 4, 4, 3, 1,

1, 5, 7, 6, 3, 1,

1, 6, 11, 11, 8, 4, 1,

1, 7, 16, 19, 17, 11, 4, 1,

1, 8, 22, 31, 32, 26, 13, 5, 1,

1, 9, 29, 48, 56, 54, 35, 17, 5, 1,

...

CROSSREFS

Cf. A156041. This is also A184957 with the last diagonal omitted.

Sequence in context: A228125 A227588 A093628 * A114282 A112739 A225640

Adjacent sequences:  A186804 A186805 A186806 * A186808 A186809 A186810

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Feb 26 2011

STATUS

approved

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Last modified June 26 10:45 EDT 2019. Contains 324375 sequences. (Running on oeis4.)