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A107984 Triangle read by rows: T(n,k)=(k+1)(n+2)(2n-k+3)(n-k+1)/6 for 0<=k<=n. 0
1, 5, 4, 14, 16, 10, 30, 40, 35, 20, 55, 80, 81, 64, 35, 91, 140, 154, 140, 105, 56, 140, 224, 260, 256, 220, 160, 84, 204, 336, 405, 420, 390, 324, 231, 120, 285, 480, 595, 640, 625, 560, 455, 320, 165, 385, 660, 836, 924, 935, 880, 770, 616, 429, 220, 506, 880 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Kekule numbers for certain benzenoids. Column 0 yields A000330. Main diagonal yields A000292. Row sums yield A006414.

REFERENCES

S. J. Cyvin and I. Gutman, Kekule structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 237, K{B(n,3,-l)}).

EXAMPLE

Triangle begins:

1;

5,4;

14,16,10;

30,40,35,20;

MAPLE

T:=proc(n, k) if k<=n then (k+1)*(n+2)*(2*n-k+3)*(n-k+1)/6 else 0 fi end: for n from 0 to 10 do seq(T(n, k), k=0..n) od; # yields sequence in triangular form

CROSSREFS

Cf. A000330, A000292, A006414.

Sequence in context: A078930 A094414 A158867 * A133178 A154225 A188627

Adjacent sequences:  A107981 A107982 A107983 * A107985 A107986 A107987

KEYWORD

nonn,tabl

AUTHOR

Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 12 2005

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Last modified February 17 12:38 EST 2012. Contains 206021 sequences.