cp's OEIS Frontend

A277987 a(n) = 100*n - 28.

%I A277987 #20 Sep 08 2022 08:46:17
%S A277987 -28,72,172,272,372,472,572,672,772,872,972,1072,1172,1272,1372,1472,
%T A277987 1572,1672,1772,1872,1972,2072,2172,2272,2372,2472,2572,2672,2772,
%U A277987 2872,2972,3072,3172,3272,3372,3472,3572,3672,3772,3872,3972
%N A277987 a(n) = 100*n - 28.
%C A277987 For n>=1, a(n) is the second Zagreb index of the tetrameric 1,3-adamantane TA[n]. The second Zagreb index of a simple connected graph is the sum of the degree products d(i)d(j) over all edges ij of the graph. The pictorial definition of the tetrameric 1,3-adamantane can be viewed in the G. H. Fath-Tabar et al. reference.
%C A277987 The M-polynomial of the tetrameric 1,3-adamantane TA[n] is M(TA[n],x,y) = 6*(n+1)*x^2*y^3 + 6*(n-1)*x^2*y^4 + (n-1)*x^4*y^4.
%H A277987 E. Deutsch and Sandi Klavzar, <a href="http://dx.doi.org/10.22052/ijmc.2015.10106">M-polynomial and degree-based topological indices</a>, Iranian J. Math. Chemistry, 6, No. 2, 2015, 93-102.
%H A277987 G. H. Fath-Tabar, A. Azad, and N. Elahinezhad, <a href="http://en.journals.sid.ir/ViewPaper.aspx?ID=254060">Some topological indices of tetrameric 1,3-adamantane</a>, Iranian J. Math. Chemistry, 1, No. 1, 2010, 111-118.
%H A277987 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A277987 G.f.: 4*(32*x - 7)/(1 - x)^2.
%F A277987 a(n) = A017293(10*n-3) for n > 0. - _Felix Fröhlich_, Nov 12 2016
%F A277987 a(n) = 2*a(n-1) - a(n-2). - _Vincenzo Librandi_, Nov 13 2016
%p A277987 seq(100*n-28, n = 0..40);
%t A277987 100*Range[0,40]-28 (* or *) LinearRecurrence[{2,-1},{-28,72},50] (* _Harvey P. Dale_, Feb 13 2018 *)
%o A277987 (PARI) a(n) = 100*n - 28 \\ _Felix Fröhlich_, Nov 12 2016
%o A277987 (Magma) [100*n-28: n in [0..40]]; // _Vincenzo Librandi_, Nov 13 2016
%Y A277987 Cf. A277986.
%K A277987 sign,easy
%O A277987 0,1
%A A277987 _Emeric Deutsch_, Nov 12 2016