A111241 - OEIS

%I #15 Apr 26 2024 14:32:15

%S 1,1,3,2,2,4,9,5,4,3,5,5,9,5,4,8,15,8,12,27,52,7,4,2,5,3,6,106,14,5,9,

%T 5,4,6,107,180,21,362,121,183,176,69,59,150,28,151,232,19,10,2,11,9,

%U 233,360,247,304,155,244,195,98,231,174,196,50,591,296,198,51,199

%N a(n) = A109735(n)/A109890(n+1).

%C This is always an integer for n>=2.

%C a(n) = 1 for n in A111315. When this happens A109890(n+1) makes a large jump. The corresponding values of A109890(n+1) are in A111316 (cf. A111242).

%H Michael De Vlieger, <a href="/A111241/b111241.txt">Table of n, a(n) for n = 2..10000</a>

%F a(n) = A094340(n) for all n > 1. - _David Wasserman_, Jan 06 2009

%e A109735(4)=12, A109890(5)=4, so a(4) = 12/4 = 3.

%t nn = 71; c[_] := False;

%t Array[Set[{a[#], c[#]}, {#, True}] &, 2]; s = a[1] + a[2];

%t Reap[Do[k = SelectFirst[Divisors[s], ! c[#] &];

%t     c[k] = True; Sow[s/k];

%t s += k, {n, 3, nn}] ][[-1, 1]] (* _Michael De Vlieger_, Apr 26 2024 *)

%Y Cf. A109735, A109890, A094340, A111315, A111316, A111242.

%Y Different from A094339.

%K nonn

%O 2,3

%A _N. J. A. Sloane_, Oct 30 2005