A020697 Number of divisors of A019505(n).

1, 2, 3, 4, 6, 8, 10, 12, 16, 20, 24, 30, 36, 48, 60, 72, 84, 96, 120, 144, 168, 192, 224, 256, 320, 384, 448, 512, 576, 672, 768, 896, 1024, 1152, 1344, 1536, 1792, 2048, 2304, 2688, 3072, 3456, 4032, 4608, 5376, 6144, 6912, 8064, 9216, 10368, 11520, 12960, 14400, 17280

Offset: 1

Author

J. Lowell, May 11 2007, corrected Mar 20 2008

Keywords

• nonn

Comments

Conjecture: all numbers of the form 3*2^n are in this sequence. - J. Lowell, Mar 12 2008 [This is false: 3*2^12 = 12288 is the smallest counterexample. - Klaus Brockhaus, Jul 24 2008]

Links

• David A. Corneth, Table of n, a(n) for n = 1..172 (first 63 terms from J. Lowell)

Crossrefs

Cf. A000005, A019505.

Formula

a(n) = A000005(A019505(n)).

Extensions

More terms from Klaus Brockhaus, Jul 24 2008