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 A289383 #16 Jul 15 2017 19:23:06 %S A289383 0,1,6,35,240,2077,23562,358775,7449060,213188689,8473977534, %T A289383 470309723435,36582636406680,3998655357260293,615328930033081458, %U A289383 133485330929459963615,40859530900982506959180,17659495180812130332490681,10781678259164073608877557286,9301770545157096607562560360595 %N A289383 Total number of nonzero vectors over all subspaces of an n-dimensional vector space over the field with two elements. %C A289383 The q-analog of A001787. %F A289383 a(n) = Sum_{k=1..n} A022166(n,k)*(2^k - 1). %F A289383 a(n)/[n]_q! is the coefficient of x^n in the expansion of x*exp_q(x)^2 when q->2 and where exp_q(x) is the q exponential function and [n]_q! is the q-factorial of n. %F A289383 a(n) = (2^n - 1)*A006116(n-1). %t A289383 nn = 20; eq[z_] :=Sum[z^n/FunctionExpand[QFactorial[n, q]], {n, 0, nn}];Table[FunctionExpand[QFactorial[n, q]] /. q -> 2, {n, 0, nn}] CoefficientList[Series[z eq[z]^2 /. q -> 2, {z, 0, nn}], z] %Y A289383 Cf. A001787, A006116, A022166. %K A289383 nonn %O A289383 0,3 %A A289383 _Geoffrey Critzer_, Jul 04 2017