login
A108669
Triangle read by rows: T(n,k) = 11*k*n + 14*(n+k) + 20 (0 <= k <= n).
0
20, 34, 59, 48, 84, 120, 62, 109, 156, 203, 76, 134, 192, 250, 308, 90, 159, 228, 297, 366, 435, 104, 184, 264, 344, 424, 504, 584, 118, 209, 300, 391, 482, 573, 664, 755, 132, 234, 336, 438, 540, 642, 744, 846, 948, 146, 259, 372, 485, 598, 711, 824, 937
OFFSET
0,1
COMMENTS
Kekulé numbers for certain benzenoids.
REFERENCES
S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 102).
FORMULA
G.f.: (20 - 6*z - t*z - 16*t*z^2 + 3*t^2*z^2)/((1-z)^2*(1-t*z)^3).
EXAMPLE
Triangle begins:
20;
34,59;
48,84,120;
62,109,156,203;
MAPLE
T:=proc(n, k) if k<=n then 11*k*n+14*(n+k)+20 else 0 fi end: for n from 0 to 10 do seq(T(n, k), k=0..n) od; # yields sequence in triangular form
MATHEMATICA
Table[11*k*n+14(n+k)+20, {n, 0, 10}, {k, 0, n}]//Flatten (* Harvey P. Dale, Jul 14 2019 *)
CROSSREFS
Sequence in context: A067468 A127906 A108667 * A293694 A039343 A043166
KEYWORD
nonn,tabl
AUTHOR
Emeric Deutsch, Jun 14 2005
STATUS
approved