A108669 Triangle read by rows: T(n,k) = 11*k*n + 14*(n+k) + 20 (0 <= k <= n).

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).

Links

Table of n, a(n) for n=0..52.

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

Adjacent sequences: A108666 A108667 A108668 * A108670 A108671 A108672

Keyword

nonn,tabl

Author

Emeric Deutsch, Jun 14 2005

Status

approved