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A185137
Tri-recursive sequence: a(n) = a(a(a(n-1))) + a(n - a(a(-3+n))) if n>6, otherwise a(n) = 1.
1
1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 12, 13, 14, 15, 15, 15, 15, 15, 15, 16, 17, 18, 20, 20, 20, 20, 20, 20, 20, 21, 22, 23, 26, 26, 26, 26, 26, 26, 26, 26, 27
OFFSET
1,7
COMMENTS
a(n-1) <= a(n) for n <= 64, but a(65)-a(64) = 32-35 < 0; first positions m where a(m) > a(m+1): 64, 79, 84, 99, 105, 106, 110, 125, 126, ... . - Reinhard Zumkeller, Jun 13 2013
MATHEMATICA
a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[5] = 1; a[6] = 1;
a[n_] := a[n] = a[a[a[n - 1]]] + a[n - a[a[-3 + n]]]
Table[a[n], {n, 1, 300}]
PROG
(Haskell)
a185137 n = a185137_list !! (n-1)
a185137_list = 1 : 1 : 1 : 1 : 1 : 1 : f 7 1 1 where
f x u v = w : f (x + 1) v w where
w = (a185137 . a185137 . a185137) (x - 1) +
a185137 (x - (a185137 . a185137) (x - 3))
-- Reinhard Zumkeller, Jun 13 2013
CROSSREFS
Sequence in context: A328865 A329623 A285762 * A368906 A368993 A137180
KEYWORD
nonn,look
AUTHOR
Roger L. Bagula, Mar 12 2012
STATUS
approved