1,1

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

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

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

Sequence in context: A082163 A074596 A087806 this_sequence A136654 A145161 A121422

Adjacent sequences: A080287 A080288 A080289 this_sequence A080291 A080292 A080293

easy,sign

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