%I #16 Jan 29 2023 19:46:19
%S 0,1,2,3,4,5,6,7,8,11,12,14,16,17,20,22,23,24,25,26,28,30,32,33,34,35,
%T 36,38,40,41,42,44,48,49,50,51,52,53,56,57,58,60,61,62,64,65,66,67,68,
%U 69,70,71,72,73,74,76,77,78,80,84,86,88,89,92,94,96,97,98,100,101,102,104,105,106,107,108,110,112,113,114,115,116,120,121
%N Numbers k such that on row k of Pascal's triangle there is no multiple of 9 which would be less than any (potential) multiple of 4 on the same row.
%C Disjoint union of {0} and the following sequences: A048278 (gives 7 other cases where there are neither multiples of 4 nor 9 on row k), A249722 (rows where a multiple of 4 is found before a multiple of 9), A249726 (cases where the least term on row k which is a multiple of 4 is also a multiple of 9, and vice versa, i.e., such a term a multiple of 36).
%C If A249717(k) < 3 then k is included in this sequence. This is a sufficient but not necessary condition, e.g., A249717(25) = 5, but 25 is also included in this sequence.
%H Antti Karttunen, <a href="/A249724/b249724.txt">Table of n, a(n) for n = 1..23590</a>
%o (PARI)
%o A249724list(upto_n) = { my(i=0, n=0, dont_print=0); while(i<upto_n,for(k=0,n\2, if(!(binomial(n,k)%4), i++;write("b249724.txt",i," ",n);dont_print=1;break, if(!(binomial(n,k)%9), dont_print=1;break))); if(!dont_print, i++;write("b249724.txt",i," ",n), dont_print=0); n++); } \\ Ugly code.
%Y Complement: A249723.
%Y Cf. A007318, A052955, A249441, A249695, A249717, A048278, A048645, A051382, A249722, A249726.
%K nonn
%O 1,3
%A _Antti Karttunen_, Nov 04 2014