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 A306108 #5 Oct 06 2018 09:38:04
%S A306108 0,1,2,3,4,5,10,20,21,30,31,32,40,41,42,43,50,51,52,53,54,101,102,103,
%T A306108 104,105,201,202,203,204,205,212,213,214,215,301,302,303,304,305,312,
%U A306108 313,314,315,323,324,325,401,402,403,404,405,412,413,414,415,423,424,425,434,435,501,502,503,504,505,512,513,514
%N A306108 Numbers with digits in {0,...,5} such that every other digit is strictly less than its neighbors.
%C A306108 Terms of A032861 written in base 6.
%F A306108 a(n) = A007092(A032861(n)).
%o A306108 (PARI) A(Nmax=100, K=5, A=[0..K], i=vector(2*K, i, max(1, i-K+1)), c(T, v)=apply(t->t+T, v))={for(n=0, oo, for(k=10, K*11, if(k%10<k\10, k%10|| i=concat(i, 1+#A))&& A=concat(A, c(k*10^n, A[i[K*n+k%10+1]..i[K*n+K+1]-1])); #A<Nmax||return(A)))}
%Y A306108 Cf. A306105 .. A306111 and A297147: analog for bases 3..9 and 10.
%Y A306108 Cf. A032862 and A032858 .. A032865 for other bases 3..10.
%K A306108 nonn,base
%O A306108 1,3
%A A306108 _M. F. Hasler_, Oct 05 2018