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 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
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS 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: A299205 A268878 A194544 * 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

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Last modified June 18 14:52 EDT 2019. Contains 324213 sequences. (Running on oeis4.)