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 A070315 #16 Oct 25 2017 06:01:54 %S A070315 1,21,161,813,3361,12421,42865,141549,453905,1426725,4422913,13579309, %T A070315 41408833,125667333,380081105,1146795693,3454279345,10392196645, %U A070315 31238454241,93845384301,281808780641,845996765061,2539181475121,7620027450733,22865249731921 %N A070315 Third diagonal of triangle in A046739. %H A070315 D. P. Roselle, <a href="http://dx.doi.org/10.1090/S0002-9939-1968-0218256-9">Permutations by number of rises and successions</a>, Proc. Amer. Math. Soc., 19 (1968), 8-16. %H A070315 D. P. Roselle, <a href="/A046739/a046739.pdf"> Permutations by number of rises and successions</a>, Proc. Amer. Math. Soc., 19 (1968), 8-16. [Annotated scanned copy] %H A070315 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (10,-40,82,-91,52,-12). %F A070315 a(n) = 3^n - (3n+2)*2^(n-1) + 2n^2. - _Ralf Stephan_, May 09 2004 %F A070315 G.f.: -x^4*(12*x^5-40*x^4+39*x^3+9*x^2-11*x-1) / ((x-1)^3*(2*x-1)^2*(3*x-1)). [_Colin Barker_, Feb 03 2013] %o A070315 (PARI) a(n) = 3^n - (3*n+2)*2^(n-1) + 2*n^2; \\ _Michel Marcus_, Oct 25 2017 %Y A070315 Cf. A046739. %K A070315 nonn,easy %O A070315 4,2 %A A070315 _N. J. A. Sloane_, May 15 2002 %E A070315 More terms from Larry Reeves (larryr(AT)acm.org), Oct 01 2002 %E A070315 More terms from _Colin Barker_, Feb 03 2013