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 A058823 #14 Aug 13 2023 02:47:22 %S A058823 1,8,36,344,3088,26216,218548,1797560,14680576,119304704,966370924, %T A058823 7809031448,62992875856,507466905128,4083900481540,32838747285128, %U A058823 263882791714816,2119341001115528,17013598599759616,136530178177126616,1095275429430191920,8784163844623695896 %N A058823 a(0) = 1, a(1) = 8; for n >= 2 a(n) is the number of degree-n monic reducible polynomials over GF(8), i.e., a(n) = 8^n - A027380(n). %C A058823 Dimensions of homogeneous subspaces of shuffle algebra over 8-letter alphabet (see A058766 for 2-letter case). %D A058823 M. Lothaire, Combinatorics on words, Cambridge mathematical library, 1983, p. 126 (definition of shuffle algebra). %t A058823 a[n_] := 8^n - DivisorSum[n, MoebiusMu[n/#] * 8^# &] / n; a[0] = 1; a[1] = 8; Array[a, 22, 0] (* _Amiram Eldar_, Aug 13 2023 *) %o A058823 (PARI) a(n) = if (n<=1, 8^n, 8^n - sumdiv(n, d, moebius(d)*8^(n/d))/n); \\ _Michel Marcus_, Oct 30 2017 %Y A058823 Cf. A001018, A027380, A058766. %K A058823 nonn %O A058823 0,2 %A A058823 Claude Lenormand (claude.lenormand(AT)free.fr), Jan 04 2001 %E A058823 Better description from Sharon Sela (sharonsela(AT)hotmail.com), Feb 19 2002 %E A058823 More terms from _Michel Marcus_, Oct 30 2017