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 A351200 #11 Feb 16 2022 16:03:41 %S A351200 1,1,3,11,53,305,2051,15731,135697,1300869,13726431,158137851, %T A351200 1975599321,26607158781,384347911211,5928465081703,97262304328573, %U A351200 1691274884085061,31073791192091251,601539400910369671,12238270940611270161,261071590963047040241 %N A351200 Number of patterns of length n with all distinct runs. %C A351200 We define a pattern to be a finite sequence covering an initial interval of positive integers. Patterns are counted by A000670 and ranked by A333217. %H A351200 Andrew Howroyd, <a href="/A351200/b351200.txt">Table of n, a(n) for n = 0..200</a> %H A351200 Mathematics Stack Exchange, <a href="https://math.stackexchange.com/q/87559">What is a sequence run? (answered 2011-12-01)</a> %e A351200 The a(1) = 1 through a(3) = 11 patterns: %e A351200 (1) (1,1) (1,1,1) %e A351200 (1,2) (1,1,2) %e A351200 (2,1) (1,2,2) %e A351200 (1,2,3) %e A351200 (1,3,2) %e A351200 (2,1,1) %e A351200 (2,1,3) %e A351200 (2,2,1) %e A351200 (2,3,1) %e A351200 (3,1,2) %e A351200 (3,2,1) %e A351200 The complement for n = 3 counts the two patterns (1,2,1) and (2,1,2). %t A351200 allnorm[n_]:=If[n<=0,{{}},Function[s,Array[Count[s,y_/;y<=#]+1&,n]] /@Subsets[Range[n-1]+1]]; %t A351200 Table[Length[Select[Join@@Permutations/@allnorm[n],UnsameQ@@Split[#]&]],{n,0,6}] %o A351200 (PARI) \\ here LahI is A111596 as row polynomials. %o A351200 LahI(n,y)={sum(k=1, n, y^k*(-1)^(n-k)*(n!/k!)*binomial(n-1, k-1))} %o A351200 S(n)={my(p=prod(k=1, n, 1 + y*x^k + O(x*x^n))); 1 + sum(i=1, (sqrtint(8*n+1)-1)\2, polcoef(p,i,y)*LahI(i,y))} %o A351200 R(q)={[subst(serlaplace(p), y, 1) | p<-Vec(q)]} %o A351200 seq(n)={my(q=S(n)); concat([1], sum(k=1, n, R(q^k-1)*sum(r=k, n, binomial(r, k)*(-1)^(r-k)) ))} \\ _Andrew Howroyd_, Feb 12 2022 %Y A351200 The version for run-lengths instead of runs is A351292. %Y A351200 A000670 counts patterns, ranked by A333217. %Y A351200 A005649 counts anti-run patterns, complement A069321. %Y A351200 A005811 counts runs in binary expansion. %Y A351200 A032011 counts patterns with distinct multiplicities. %Y A351200 A044813 lists numbers whose binary expansion has distinct run-lengths. %Y A351200 A060223 counts Lyndon patterns, necklaces A019536, aperiodic A296975. %Y A351200 A131689 counts patterns by number of distinct parts. %Y A351200 A238130 and A238279 count compositions by number of runs. %Y A351200 A297770 counts distinct runs in binary expansion. %Y A351200 A345194 counts alternating patterns, up/down A350354. %Y A351200 Counting words with all distinct runs: %Y A351200 - A351013 = compositions, for run-lengths A329739, ranked by A351290. %Y A351200 - A351016 = binary words, for run-lengths A351017. %Y A351200 - A351018 = binary expansions, for run-lengths A032020, ranked by A175413. %Y A351200 - A351202 = permutations of prime factors. %Y A351200 - A351642 = word structures. %Y A351200 Row sums of A351640. %Y A351200 Cf. A003242, A098504, A098859, A106356, A242882, A325545, A328592, A329740, A351014, A351204, A351291. %K A351200 nonn %O A351200 0,3 %A A351200 _Gus Wiseman_, Feb 09 2022 %E A351200 Terms a(10) and beyond from _Andrew Howroyd_, Feb 12 2022