A117669 The n-th n-gonal number divisible by n.

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

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 11 2006

Keywords

• nonn

Examples

			The 5th number in the sequence must be the 5th pentagonal (5-gonal) number which can be divided by 5, namely 210.
		

Crossrefs

Cf. A057145.

Programs

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 *)

Extensions

Offset and 2nd term corrected by R. J. Mathar, Nov 22 2022