A239433 Numbers m with at least one integer solution for x' = m, where x' is the arithmetic derivative of x (cf. A003415).

4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 66, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 80, 81

Offset: 1

Author

Reinhard Zumkeller, Mar 18 2014

Keywords

• nonn

Comments

A099302(a(n)) > 0.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A002620, A098700 (complement), A369251 (subsequence).

Programs

Haskell

a239433 n = a239433_list !! (n-1)
a239433_list = filter
   (\z -> any (== z) $ map a003415 $ takeWhile (<= a002620 z) a013929_list) [2..]