A117053 Enneagonal numbers for which both the sum of the digits and the product of the digits are also enneagonal numbers.

0, 1, 9, 1350, 10071, 39804, 46806, 66309, 80484, 175056, 204369, 226950, 235950, 260169, 305916, 450186, 460284, 473064, 556206, 570246, 581604, 676500, 704481, 733029, 822075, 835701, 930606, 1015476, 1065084, 1155750, 1208634, 1305096

Offset

0,3

Comments

An enneagopnal number is also called a nonagonal number. - Harvey P. Dale, Apr 13 2020

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Example

39804 is in the sequence because (1) it is an enneagonal number,(2)the sum of its digits 3+9+8+0+4=24 is an enneagonal number and (3)the product of its digits 3*9*8*0*4=0 is also an enneagonal number.

Mathematica

With[{nnn=Table[(n(7n-5))/2, {n, 0, 1000}]}, Select[nnn, MemberQ[nnn, Total[ IntegerDigits[ #]]]&&MemberQ[nnn, Times@@IntegerDigits[#]]&]] (* Harvey P. Dale, Apr 13 2020 *)

Crossrefs

Cf. A001106.

Sequence in context: A266864 A076442 A076704 * A270067 A213448 A120347

Adjacent sequences: A117050 A117051 A117052 * A117054 A117055 A117056

Keyword

base,nonn

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 15 2006

Status

approved