A080290 a(n) = n^n * (n + 2 - (1/12) * (n^2-1)).

3, 15, 117, 1216, 15625, 237168, 4117715, 79691776, 1678822119, 37500000000, 855935011833, 18575209267200, 302875106592253, -2778001706389504, -729823150634765625, -59951918239556042752, -4136201309431683820885

Offset

1,1

Comments

a(n) is the determinant of the n X n matrix M with M(i,i)=2i+n, M(i,j)=i+j.

Links

Table of n, a(n) for n=1..17.

Formula

a(n)=n^n(n+2-(1/12)(n^2-1)). a(n)=n^n-n^(n-1)A002378(n)-n^(n-2)A002415

Mathematica

Table[n^n(n + 2 - (n^2 - 1)/12), {n, 1, 17}]

Crossrefs

Sequence in context: A087806 A245043 A225109 * A371984 A365777 A372161

Adjacent sequences: A080287 A080288 A080289 * A080291 A080292 A080293

Keyword

easy,sign

Author

Mario Catalani (mario.catalani(AT)unito.it), Feb 13 2003

Status

approved