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

1,2

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)

Formula

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

Crossrefs

Cf. A000005, A019505.

Sequence in context: A341016 A200678 A088881 * A175381 A369519 A213623

Adjacent sequences: A020694 A020695 A020696 * A020698 A020699 A020700

Keyword

nonn

Author

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

Extensions

More terms from Klaus Brockhaus, Jul 24 2008

Status

approved