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a(n) = 2n*(n+1)*(2n+1).
2

%I #93 Apr 29 2020 10:07:34

%S 0,12,60,168,360,660,1092,1680,2448,3420,4620,6072,7800,9828,12180,

%T 14880,17952,21420,25308,29640,34440,39732,45540,51888,58800,66300,

%U 74412,83160,92568,102660,113460,124992,137280,150348,164220,178920,194472,210900,228228

%N a(n) = 2n*(n+1)*(2n+1).

%C The altitude h(n) = a(n)/A001844(n) of the (A005408(n), A046092(n) and A001844(n)) rectangular triangle is an irreducible fraction. - _Ralf Steiner_, Feb 25 2020

%C In this case, area A = a(n)/2 = A055112(n). - _Bernard Schott_, Feb 27 2020

%H S. P. Borgatti and M. G. Everett, <a href="http://www.jstor.org/stable/270991">Notions of Position in Social Network Analysis</a>, Sociological Methodology, 22 (1992), 1-35.

%H C. Purcell and P. Rombach, <a href="https://arxiv.org/abs/1802.10180">Role colouring graphs in hereditary classes</a>, arXiv:1802.10180 [math.CO], 2018.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).

%F a(n) = 12*A000330(n).

%F G.f.: 12*x*(1+x)/(1-x)^4. - _Colin Barker_, Mar 12 2018

%F a(n) = 6*A006331(n) = 4*A059270(n) = 3*A002492(n) = 2*A055112(n). - _Omar E. Pol_, Apr 04 2018

%F From _Ralf Steiner_, Feb 27 2020: (Start)

%F a(n) = 2*n*A000384(n+1).

%F a(n) = sqrt(A016754(n)*A060300(n)).

%F (End)

%F a(n) = A005408(n) * A046092(n). - _Bruce J. Nicholson_, Apr 24 2020

%Y Cf. A000330, A002492, A006331, A055112, A059270, A005408, A046092, A001844, A000384, A016754, A060300.

%Y Cf. A027480.

%K nonn,easy

%O 0,2

%A _Christopher Purcell_, Mar 12 2018

%E Edited by _N. J. A. Sloane_, Aug 01 2019