login
A192827
Molecular topological indices of the gear graphs
1
11, 88, 231, 440, 715, 1056, 1463, 1936, 2475, 3080, 3751, 4488, 5291, 6160, 7095, 8096, 9163, 10296, 11495, 12760, 14091, 15488, 16951, 18480, 20075, 21736, 23463, 25256, 27115, 29040
OFFSET
1,1
COMMENTS
Gear graphs are defined for n>=3; extended to n=1 using closed form
LINKS
Eric Weisstein's World of Mathematics, Gear Graph
Eric Weisstein's World of Mathematics, Molecular Topological Index
FORMULA
a(n) = 11*n*(3*n-2).
a(n) = 11*A000567(n).
G.f.: 11*x*(1+5*x)/(1-x)^3. - Colin Barker, Nov 04 2012
E.g.f.: 11*x*(1+3*x)*exp(x). - G. C. Greubel, Jan 03 2019
MATHEMATICA
Table[11n(3n-2), {n, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {11, 88, 231}, 40] (* Harvey P. Dale, Dec 21 2018 *)
PROG
(PARI) a(n)=11*n*(3*n-2) \\ Charles R Greathouse IV, Jun 17 2017
(Magma) [11*n*(3*n-2): n in [1..40]]; // G. C. Greubel, Jan 03 2019
(Sage) [11*n*(3*n-2) for n in (1..40)] # G. C. Greubel, Jan 03 2019
CROSSREFS
Cf. A000567.
Sequence in context: A001278 A125304 A334249 * A022735 A346448 A173731
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jul 11 2011
STATUS
approved