This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A136392 #66 Sep 02 2025 11:00:29
%S A136392 1,9,29,61,105,161,229,309,401,505,621,749,889,1041,1205,1381,1569,
%T A136392 1769,1981,2205,2441,2689,2949,3221,3505,3801,4109,4429,4761,5105,
%U A136392 5461,5829,6209,6601,7005,7421,7849,8289,8741,9205,9681,10169,10669,11181,11705,12241
%N A136392 a(n) = 6*n^2 - 10*n + 5.
%C A136392 Binomial transform of [1, 8, 12, 0, 0, 0, ...].
%C A136392 Numbers k such that 6*k - 5 is the square of a number of the form 6*k - 5, contained in A199859. - _Eleonora Echeverri-Toro_, Nov 29 2011
%C A136392 Central terms of the triangle A033292. - _Reinhard Zumkeller_, Feb 06 2012
%C A136392 Sequence found by reading the line from 1, in the direction 1, 9, ..., in the square spiral whose vertices are the generalized pentagonal numbers A001318. - _Omar E. Pol_, Jul 18 2012
%H A136392 Kelvin Voskuijl, <a href="/A136392/b136392.txt">Table of n, a(n) for n = 1..10000</a>
%H A136392 John Elias, <a href="/A136392/a136392.png">Illustration: Centered nesting cube frames</a>.
%H A136392 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A136392 a(n) = n*(3*n - 2) + (n-1)*(3*n - 5), n > 1.
%F A136392 a(n) = n*A016777(n-1) + (n-1)*A016777(n-2).
%F A136392 a(n) = a(n-1) + 12*n - 16 (with a(1)=1). - _Vincenzo Librandi_, Nov 24 2010
%F A136392 G.f.: x*(1+x)*(1+5*x)/(1-x)^3. - _Colin Barker_, Jan 09 2012
%F A136392 a(n) = 1 + A033580(n-1). - _Omar E. Pol_, Jul 18 2012
%F A136392 a(n) = A059722(n) - A059722(n-1). - _J. M. Bergot_, Nov 02 2012
%F A136392 a(n) = A000567(n-1) + A000567(n). - _Charlie Marion_, May 29 2024
%F A136392 From _Elmo R. Oliveira_, Oct 31 2024: (Start)
%F A136392 E.g.f.: exp(x)*(2*x*(3*x - 2) + 5) - 5.
%F A136392 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 3. (End)
%t A136392 Table[6n^2-10n+5,{n,50}] (* or *) LinearRecurrence[{3,-3,1},{1,9,29},50] (* _Harvey P. Dale_, Mar 05 2023 *)
%o A136392 (PARI) a(n)=6*n^2-10*n+5 \\ _Charles R Greathouse IV_, Nov 29 2011
%o A136392 (Haskell)
%o A136392 a136392 n = 2 * n * (3*n - 5) + 5 -- _Reinhard Zumkeller_, Feb 06 2012
%Y A136392 Cf. A000567, A001318, A016777, A033292, A033580, A059722, A199859, A201279, A204675.
%K A136392 nonn,easy,changed
%O A136392 1,2
%A A136392 _Gary W. Adamson_, Dec 28 2007