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 A000943 M1352 N0519 #16 Dec 09 2014 00:25:56 %S A000943 1,2,5,8,18,29,57,96,183,318,604,1080,2047,3762,7145,13354,25471, %T A000943 48164,92193,175780,337581,647313,1246849,2400828,4636375,8956045, %U A000943 17334785,33570800,65108045,126355319,245492226,477284164,928772631,1808538336 %N A000943 Number of combinatorial types of simplicial n-dimensional polytopes with n+3 nodes. %D A000943 B. Grünbaum, Convex Polytopes. Wiley, NY, 1967, p. 424. %D A000943 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A000943 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %p A000943 with(numtheory); n := 50; for d from 2 to n do C(d) := 0; for h from 1 to d+3 do if (h mod 2 = 1) and (d+3 mod h = 0) then C(d) := C(d) + phi(h) * 2^((d+3)/h); fi; od; C(d) := 2^(floor(d/2)) - floor ((d+4)/2) + C(d)/(4*(d+3)); od: A000943 := n-> eval(C(n)); %t A000943 a[ n_ ] := 2^Floor[ n/2 ]-Floor[ (n+4)/2 ]+(1/(4*(n+3)))*Plus@@Map[ EulerPhi[ # ]*2^((n+3)/#)&, Select[ Divisors[ n+3 ], OddQ ] ] %Y A000943 Cf. A049337, A000944. %K A000943 nonn,nice %O A000943 1,2 %A A000943 _N. J. A. Sloane_ %E A000943 n=12 term corrected (typo in reference), formula (due to Perles) and more terms from Lukas Finschi (finschi(AT)ifor.math.ethz.ch), Mar 06 2001