A117084 Octagonal numbers for which both the sum and the product of the digits is also an octagonal number.

0, 1, 8, 1160, 20501, 30401, 42960, 90480, 131880, 168033, 181056, 208560, 238008, 269400, 302736, 338016, 375240, 414408, 455520, 520833, 590520, 690240, 743016, 770133, 854400, 913008, 943041, 1004565, 1036056, 1068033, 1100496, 1235208

Offset

0,3

Links

Table of n, a(n) for n=0..31.

Example

42960 is in the sequence because (1) it is an octagonal number, the sum of its digits 4+2+9+6+0 = 21 is an octagonal number and (3) the product of its digits 4*2*9*6*0 = 0 is also an octagonal number.

Crossrefs

Cf. A000567.

Sequence in context: A357543 A003767 A221084 * A201985 A301614 A180767

Adjacent sequences: A117081 A117082 A117083 * A117085 A117086 A117087

Keyword

base,nonn

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 17 2006

Status

approved