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A139098 8n^2. 16


%S 0,8,32,72,128,200,288,392,512,648,800,968,1152,1352,1568,1800,2048,

%T 2312,2592,2888,3200,3528,3872,4232,4608,5000,5408,5832,6272,6728,

%U 7200,7688,8192,8712,9248,9800,10368,10952,11552,12168,12800

%N 8n^2.

%C Opposite numbers to the centered 16-gonal numbers (A069129) in the square spiral whose vertices are the triangular numbers (A000217).

%C 8 times the squares. [From Omar E. Pol, Dec 09 2008]

%C a(n-1) is the molecular topological index of the n-wheel graph W_n - Eric Weisstein, Jul 11 2011

%C An n * n pandiagonal magic square has a(n) orientations - Kausthub Gudipati, Sep 15, 2011

%H Vincenzo Librandi, <a href="/A139098/b139098.txt">Table of n, a(n) for n = 0..800</a>

%H Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MolecularTopologicalIndex.html">Molecular Topological Index</a>

%F a(n) = A000290(n)*8. [From Omar E. Pol, Dec 09 2008]

%F a(n) = A001105(n)*4 = A016742(n)*2. [From Omar E. Pol, Dec 13 2008]

%t s=0;lst={s};Do[s+=n++ +8;AppendTo[lst, s], {n, 0, 8!, 16}];lst [From Vladimir Orlovsky, Nov 16 2008]

%o (MAGMA) [8*n^2: n in [0..50]]; // Vincenzo Librandi, Apr 26 2011

%Y Cf. A000217, A000290, A016766, A033582, A069129, A001105, A016742.

%K easy,nonn

%O 0,2

%A _Omar E. Pol_, Apr 25 2008

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Last modified April 20 06:17 EDT 2014. Contains 240779 sequences.