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A117053 Enneagonal numbers for which both the sum of the digits and the product of the digits are also enneagonal numbers. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified December 4 09:10 EST 2020. Contains 338921 sequences. (Running on oeis4.)