login
a(n) is the number of distinct possible values of d(k), the number of divisors of k, among numbers k whose binary order (A029837) does not exceed n.
4

%I #17 May 14 2018 20:25:22

%S 1,2,3,4,6,7,11,12,16,17,23,26,31,37,43,48,58,64,74,82,94,106,122,133,

%T 146,165,183,202,224,244,267,294,325,355,389,416,453,500,541,584,636,

%U 680,737,795,859,922,995,1068,1149,1233,1324,1412,1523,1616,1731,1845

%N a(n) is the number of distinct possible values of d(k), the number of divisors of k, among numbers k whose binary order (A029837) does not exceed n.

%H David A. Corneth, <a href="/A036470/b036470.txt">Table of n, a(n) for n = 0..63</a>

%e If 1 <= k <= 128, i.e., the binary order of k is g(k) <= 7, then d(k) takes 12 values {1,2,3,4,5,6,7,8,9,10,12,16}; thus a(7) = 12. The maximal value (16) appears as a(7) in A036451.

%Y Cf. A000005, A005179, A029837, A036471, A036493.

%K nonn

%O 0,2

%A _Labos Elemer_

%E a(20)-a(21) corrected by _David A. Corneth_, May 12 2018