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 A056276 #9 Jan 18 2022 15:36:29
%S A056276 1,1,4,13,51,196,854,3830,17997,86419,422004,2079260,10306751,
%T A056276 51263086,255514299,1275160060,6368612301,31821454413,159042661904,
%U A056276 795019250650,3974515029793,19870830290476,99348921288654,496728909635860,2483597478617750,12417846151236799
%N A056276 Number of primitive (aperiodic) word structures of length n using a 5-ary alphabet.
%C A056276 Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same structure.
%D A056276 M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
%F A056276 a(n) = Sum_{d|n} mu(d)*A056272(n/d).
%Y A056276 Cf. A008683, A054720.
%K A056276 nonn
%O A056276 1,3
%A A056276 _Marks R. Nester_