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 A170790 #26 Sep 08 2022 08:45:49
%S A170790 0,1,65792,64579923,8590065664,381470703125,8463334761216,
%T A170790 116315277170407,1125899973951488,8338591043543529,50000000500000000,
%U A170790 252723515428620731,1109305555950108672,4325207964992918653
%N A170790 a(n) = n^9*(n^8 + 1)/2.
%C A170790 Number of unoriented rows of length 17 using up to n colors. For a(0)=0, there are no rows using no colors. For a(1)=1, there is one row using that one color for all positions. For a(2)=65792, there are 2^17=131072 oriented arrangements of two colors. Of these, 2^9=512 are achiral. That leaves (131072-512)/2=65280 chiral pairs. Adding achiral and chiral, we get 65792. - _Robert A. Russell_, Nov 13 2018
%H A170790 Vincenzo Librandi, <a href="/A170790/b170790.txt">Table of n, a(n) for n = 0..10000</a>
%H A170790 <a href="/index/Rec#order_18">Index entries for linear recurrences with constant coefficients</a>, signature (18,-153,816,-3060,8568,-18564, 31824,-43758,48620,-43758,31824,-18564,8568,-3060,816,-153,18,-1).
%F A170790 G.f.: (x + 65774*x^2 + 63395820*x^3 + 7437692410*x^4 + 236676566180*x^5 + 2858646249342*x^6 + 15527826341908*x^7 + 41568611082650*x^8 + 57445191259830*x^9 + 41568611082650*x^10 + 15527826341908*x^11 + 2858646249342*x^12 + 236676566180*x^13 + 7437692410*x^14 + 63395820*x^15 + 65774*x^16 + x^17)/(1-x)^18. - _G. C. Greubel_, Dec 06 2017
%F A170790 From _Robert A. Russell_, Nov 13 2018: (Start)
%F A170790 a(n) = (A010805(n) + A001017(n)) / 2 = (n^17 + n^9) / 2.
%F A170790 G.f.: (Sum_{j=1..17} S2(17,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=1..9} S2(9,j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
%F A170790 G.f.: x*Sum_{k=0..16} A145882(17,k) * x^k / (1-x)^18.
%F A170790 E.g.f.: (Sum_{k=1..17} S2(17,k)*x^k + Sum_{k=1..9} S2(9,k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
%F A170790 For n>17, a(n) = Sum_{j=1..18} -binomial(j-19,j) * a(n-j). (End)
%t A170790 Table[(n^9 (n^8+1))/2,{n,0,20}] (* _Harvey P. Dale_, Oct 03 2016 *)
%o A170790 (Magma) [n^9*(n^8+1)/2: n in [0..20]]; // _Vincenzo Librandi_, Aug 26 2011
%o A170790 (PARI) for(n=0,30, print1(n^9*(n^8+1)/2, ", ")) \\ _G. C. Greubel_, Dec 06 2017
%o A170790 (Sage) [n^9*(n^8+1)/2 for n in range(30)] # _G. C. Greubel_, Nov 15 2018
%o A170790 (GAP) List([0..30], n -> n^9*(n^8+1)/2); # _G. C. Greubel_, Nov 15 2018
%o A170790 (Python) for n in range(0,20): print(int(n**9*(n**8 + 1)/2), end=', ') # _Stefano Spezia_, Nov 15 2018
%Y A170790 Row 17 of A277504.
%Y A170790 Cf. A010805 (oriented), A001017 (achiral).
%K A170790 nonn,easy
%O A170790 0,3
%A A170790 _N. J. A. Sloane_, Dec 11 2009