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A117669
The n-th n-gonal number divisible by n.
1
1, 4, 15, 64, 210, 630, 1288, 736, 4959, 9850, 14421, 6336, 34840, 57134, 20805, 28288, 141933, 208818, 253099, 89200, 107856, 583462, 680340, 56304, 1045675, 1367210, 1553553, 497056, 2242164, 687090, 3155986, 979456, 1092861, 5336674, 1580845, 1779408, 7797898, 9370838, 2622789, 756400
OFFSET
1,2
EXAMPLE
The 5th number in the sequence must be the 5th pentagonal (5-gonal) number which can be divided by 5, namely 210.
MAPLE
A117669 := proc(n)
fdiv := 0 ;
for i from 1 do
if modp(A057145(n, i), n) = 0 then
fdiv := fdiv+1 ;
if fdiv = n then
return A057145(n, i) ;
end if;
end if;
end do:
end proc:
seq(A117669(n), n=1..40) ; # R. J. Mathar, Nov 22 2022
MATHEMATICA
Table[Select[PolygonalNumber[n, Range[2000]], Mod[#, n]==0&][[n]], {n, 40}] (* Harvey P. Dale, Jun 08 2024 *)
CROSSREFS
Cf. A057145.
Sequence in context: A027216 A124541 A353264 * A323789 A341922 A007526
KEYWORD
nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 11 2006
EXTENSIONS
Offset and 2nd term corrected by R. J. Mathar, Nov 22 2022
STATUS
approved