A075770 Let u(1)=u(2)=u(3)=1, u(n+3)=(n*u(n)+(n+1)*u(n+1)+(n+2)*u(n+2))/(n+3); sequence gives values of n such that u(n) is an integer.

1, 2, 3, 10, 14, 350, 702, 817, 1053, 1405, 31426, 44770, 86766, 120118, 216918, 284310, 343278, 347646, 426465, 511758, 767637, 1005030, 1282398, 1483326, 1610510, 1930666, 2434318, 2643990, 2883465, 3345210, 3367430, 3420670, 3647278

Offset

1,2

Links

Table of n, a(n) for n=1..33.

Mathematica

a[1] = a[2] = a[3] = 1; a[n_] := a[n] = ((n - 3)*a[n - 3] + (n - 2)*a[n - 2] + (n - 1)*a[n - 1])/n; Flatten[ Position[ Table[a[n], {n, 1, 10^5}], _Integer]]

Crossrefs

Sequence in context: A268878 A194544 A348475 * A135101 A108065 A187767

Adjacent sequences: A075767 A075768 A075769 * A075771 A075772 A075773

Keyword

nonn

Author

Benoit Cloitre, Oct 09 2002

Extensions

Edited, corrected and extended by Robert G. Wilson v, Oct 10 2002

a(14) omwards from Lambert Klasen (lambert.klasen(AT)gmx.net), Jul 27 2005

Status

approved