A118559 Lucky numbers for which both the sum of the digits and the product of the digits is also a lucky number.

1, 3, 7, 9, 111, 133, 135, 171, 331, 357, 535, 537, 553, 717, 735, 11113, 11137, 11173, 11371, 11373, 11535, 11731, 11911, 13113, 13117, 13179, 13317, 13335, 13371, 13515, 13533, 13551, 15333, 15511, 15531, 17313, 17391, 17737, 17913, 17997

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

133 is in the sequence because: (1) it is a lucky number, (2) the sum of its digits 1+3+3=7 is a lucky number, (3) the product of its digits 1*3*3=9 is a lucky number.

Mathematica

lst = Range[1, 19172, 2]; i = 2; While[ i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; Select[lst, MemberQ[lst, Plus @@ IntegerDigits@# ] && MemberQ[lst, Times @@ IntegerDigits@# ] &] (* Robert G. Wilson v *)

Crossrefs

Cf. A000959, A007953, A007954.

Sequence in context: A363572 A337613 A152607 * A189244 A127789 A112105

Adjacent sequences: A118556 A118557 A118558 * A118560 A118561 A118562

Keyword

base,nonn

Author

Luc Stevens (lms022(AT)yahoo.com), May 07 2006

Extensions

Corrected and extended by Adam Panagos (adam.panagos(AT)gmail.com) and Robert G. Wilson v, May 10 2006

Status

approved