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Enneagonal numbers divisible by 9.
1

%I #8 Mar 22 2021 05:47:34

%S 0,9,261,396,1089,1350,2484,2871,4446,4959,6975,7614,10071,10836,

%T 13734,14625,17964,18981,22761,23904,28125,29394,34056,35451,40554,

%U 42075,47619,49266,55251,57024,63450,65349,72216,74241,81549,83700,91449

%N Enneagonal numbers divisible by 9.

%C Intersection of A008591 and A001106. - _Michel Marcus_, Feb 27 2014

%H Amiram Eldar, <a href="/A117796/b117796.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Table[PolygonalNumber[9, n], {n, 0, 170}], Divisible[#, 9] &] (* _Amiram Eldar_, Mar 22 2021 *)

%o (PARI) isok(n) = ispolygonal(n, 9) && !(n % 9); \\ _Michel Marcus_, Feb 27 2014

%Y Cf. A001106, A008591.

%K easy,nonn

%O 1,2

%A Luc Stevens (lms022(AT)yahoo.com), Apr 29 2006