cp's OEIS Frontend

A205388 Least s(k) such that n divides s(k)-s(j) for some j where s(j)=(1/2)C(2j,j).

%I A205388 #11 Dec 25 2023 18:17:31
%S A205388 3,3,10,35,35,462,10,35,10,1716,1716,462,126,462,1716,35,35,24310,
%T A205388 1716,6435,462,1716,92378,462,35,24310,462,462,126,1716,352716,35,
%U A205388 1716,35,1716,24310,24310,1716,6435,6435,126,462,77558760,24310,24310
%N A205388 Least s(k) such that n divides s(k)-s(j) for some j<k, where s(j)=(1/2)C(2j,j).
%C A205388 For a guide to related sequences, see A204892.
%H A205388 Robert Israel, <a href="/A205388/b205388.txt">Table of n, a(n) for n = 1..10000</a>
%p A205388 N:= 100: # for a(1)..a(N)
%p A205388 S:=proc(j) option remember; binomial(2*j,j)/2 end proc:
%p A205388 A:= Vector(N): T:= {$1..N}:
%p A205388 for k from 2 while T <> {} do
%p A205388   for j from 1 to k-1 while T <>{} do
%p A205388     w:= S(k)-S(j);
%p A205388     d:= select(t -> w mod t = 0, T);
%p A205388     A[convert(d,list)]:= S(k);
%p A205388     T:= T minus d;
%p A205388   od;
%p A205388 od;
%p A205388 convert(A,list); # _Robert Israel_, Aug 28 2019
%t A205388 (See the program at A205386.)
%Y A205388 Cf. A205386, A204892.
%K A205388 nonn
%O A205388 1,1
%A A205388 _Clark Kimberling_, Jan 27 2012