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 A362421 #11 May 13 2023 06:18:55 %S A362421 1,1,2,1,0,1,2,2,0,1,0,1,0,0,3,1,0,1,0,0,0,1,0,2,0,2,0,1,0,1,2,0,0,0, %T A362421 0,1,0,0,0,1,0,1,0,0,0,1,0,2,0,0,0,1,0,0,0,0,0,1,0,1,0,0,4,0,0,1,0,0, %U A362421 0,1,0,1,0,0,0,0,0,1,0,3,0,1,0,0,0,0,0 %N A362421 Number of nonisomorphic vector spaces consisting of n elements. %C A362421 If n is a prime power p^k, then a vector space consisting of n elements has the form (F_(p^d))^(k/d) where d is a divisor of k. %H A362421 Philip Turecek, <a href="/A362421/b362421.txt">Table of n, a(n) for n = 2..1000</a> %F A362421 a(n) = a(p^k) = sigma_0(k) if n = p^k is a prime power, a(n) = 0 otherwise. %e A362421 a(16) = 3 because 16=2^4 and 4 has 3 divisors. %o A362421 (Sage) %o A362421 def f(a): %o A362421 if not a.is_prime_power(): return 0 %o A362421 else: return sigma(factor(a)[0][1],0) %K A362421 nonn %O A362421 2,3 %A A362421 _Philip Turecek_, Apr 19 2023