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

1,2

Links

Table of n, a(n) for n=1..40.

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

Crossrefs

Cf. A057145.

Sequence in context: A027216 A124541 A353264 * A323789 A341922 A007526

Adjacent sequences: A117666 A117667 A117668 * A117670 A117671 A117672

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