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 A111685 #18 Feb 16 2025 08:32:58
%S A111685 1,8,75,984,17045,366288,9374967,278095760,9375293169,353906211240,
%T A111685 14785127222723,677150215857192,33734100501544365,1816008001717251104,
%U A111685 105048613959883117935,6497985798745934394528,427999600108502895779657
%N A111685 n + n(n+1) + n(n+1)(n+2) + ..., with n terms.
%H A111685 Robert Israel, <a href="/A111685/b111685.txt">Table of n, a(n) for n = 1..364</a>
%H A111685 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RisingFactorial.html">Rising Factorial.</a>
%e A111685 a(3) = 3+ 3*4 +3*4*5 = 75.
%p A111685 seq(add(pochhammer(n,i),i=1..n),n=1..20); # _Robert Israel_, Aug 18 2024
%t A111685 Table[Total[Rest[FoldList[Times,1,Range[n,2n-1]]]],{n,20}] (* _Harvey P. Dale_, Apr 22 2011 *)
%t A111685 Table[Total[Pochhammer[n, Range[n]]], {n, 20}] (* _T. D. Noe_, Apr 22 2011 *)
%o A111685 (PARI) a(n) = sum(k=0,n-1,prod(j=0,k,n+j)) \\ _Rick L. Shepherd_, Aug 16 2005
%Y A111685 Cf. A054654.
%K A111685 nonn
%O A111685 1,2
%A A111685 _Amarnath Murthy_, Aug 16 2005
%E A111685 More terms from _Rick L. Shepherd_, Aug 16 2005