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 A382856 #9 Apr 07 2025 09:26:41 %S A382856 1,3,5,7,9,11,13,15,17,18,19,21,23,25,27,29,31,33,35,37,39,41,43,45, %T A382856 47,49,50,51,53,54,55,57,59,61,63,65,67,69,71,73,75,77,79,81,83,85,87, %U A382856 89,90,91,93,95,97,98,99,101,103,105,107,108,109,111,113,115 %N A382856 Numbers whose prime indices do not have a mode of 1. %e A382856 The terms together with their prime indices begin: %e A382856 1: {} %e A382856 3: {2} %e A382856 5: {3} %e A382856 7: {4} %e A382856 9: {2,2} %e A382856 11: {5} %e A382856 13: {6} %e A382856 15: {2,3} %e A382856 17: {7} %e A382856 18: {1,2,2} %e A382856 19: {8} %e A382856 21: {2,4} %e A382856 23: {9} %e A382856 25: {3,3} %e A382856 27: {2,2,2} %t A382856 prix[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]; %t A382856 Select[Range[100],FreeQ[Commonest[prix[#]],1]&] %Y A382856 The case of non-unique mode is A024556. %Y A382856 The complement is A360015 except first. %Y A382856 Partitions of this type are are counted by A382526 except first, complement A241131. %Y A382856 A091602 counts partitions by the greatest multiplicity, rank statistic A051903. %Y A382856 A112798 lists prime indices, length A001222, sum A056239. %Y A382856 A116598 counts ones in partitions, rank statistic A007814. %Y A382856 A240312 counts partitions with max part = max multiplicity, ranks A381542. %Y A382856 A362611 counts modes in prime indices, triangle A362614. %Y A382856 For co-mode see A359178, A362613, A364061 (A364062), A364158 (A364159). %Y A382856 Cf. A000265, A002865, A106529, A327473, A327476, A362605, A363486, A356862, A360013, A360014, A381437. %K A382856 nonn %O A382856 1,2 %A A382856 _Gus Wiseman_, Apr 07 2025