A117604 Padovan numbers which can be divided by their multiplicative digital root.

1, 2, 3, 4, 5, 7, 9, 12, 616, 816, 1432, 1618192

Offset: 1

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 05 2006

Keywords

• nonn
• base

Comments

a(13), if it exists, is A000931(m) for some m >= 25000, and thus has over 3000 digits. - Nathaniel Johnston, May 05 2011

Crossrefs

Cf. A000931, A031347.

Programs

Mathematica

p=Rest[Union[LinearRecurrence[{0, 1, 1}, {1, 0, 0}, 71]]];Select[p,NestWhile[Times@@IntegerDigits[#] &, #, # > 9 &]>0&&Divisible[#,NestWhile[Times@@IntegerDigits[#] &, #, # > 9 &]]&] (* James C. McMahon, Sep 26 2024 *)

Extensions

Offset changed from 0 to 1 and a(12) from Nathaniel Johnston, May 05 2011