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 A382772 #7 Apr 09 2025 23:39:22 %S A382772 1,6,12,96,360,1536,3456,5184,5760,6144,7776,13824,23040,24576,55296, %T A382772 62208,92160 %N A382772 Set of positions of first appearances in A382771 (permutations of prime indices with distinct run-lengths). %e A382772 The permutations for n = 12, 96, 360, 1536: %e A382772 (1,1,2) (1,1,1,1,1,2) (1,1,1,2,2,3) (1,1,1,1,1,1,1,1,1,2) %e A382772 (2,1,1) (1,1,1,2,1,1) (1,1,1,3,2,2) (1,1,1,1,1,1,1,2,1,1) %e A382772 (1,1,2,1,1,1) (2,2,1,1,1,3) (1,1,1,1,1,1,2,1,1,1) %e A382772 (2,1,1,1,1,1) (2,2,3,1,1,1) (1,1,1,1,1,2,1,1,1,1) %e A382772 (3,1,1,1,2,2) (1,1,1,1,2,1,1,1,1,1) %e A382772 (3,2,2,1,1,1) (1,1,1,2,1,1,1,1,1,1) %e A382772 (1,1,2,1,1,1,1,1,1,1) %e A382772 (2,1,1,1,1,1,1,1,1,1) %t A382772 y=Table[Length[Select[Permutations[Join@@ConstantArray@@@FactorInteger[n]],UnsameQ@@Length/@Split[#]&]],{n,0,100000}]; %t A382772 fip[y_]:=Select[Range[Length[y]],!MemberQ[Take[y,#-1],y[[#]]]&]; %t A382772 fip[Rest[y]] %Y A382772 Positions of first appearances in A382771, by signature A382773. %Y A382772 For equal run-lengths we have A382878, firsts of A382857, zeros A382879. %Y A382772 A044813 lists numbers whose binary expansion has distinct run-lengths, equal A140690. %Y A382772 A055396 gives least prime index, greatest A061395. %Y A382772 A056239 adds up prime indices, row sums of A112798. %Y A382772 A098859 counts partitions with distinct multiplicities, ordered A242882. %Y A382772 A239455 counts Look-and-Say partitions, ranks A351294, conjugate A381432. %Y A382772 A328592 lists numbers whose binary form has distinct runs of ones, equal A164707. %Y A382772 A329738 counts compositions with equal run-lengths, ranks A353744. %Y A382772 A329739 counts compositions with distinct run-lengths, ranks A351596. %Y A382772 A351293 counts non-Look-and-Say partitions, ranks A351295, conjugate A381433. %Y A382772 Cf. A000720, A001221, A001222, A003242, A048767, A130091, A238130, A305936, A351013, A351202, A382876. %K A382772 nonn,more %O A382772 1,2 %A A382772 _Gus Wiseman_, Apr 09 2025