A139127 Greatest preceding term in Hofstadter sequence A005244 that is a divisor of A005244(n)+1; a(1) = 1.

1, 2, 3, 5, 5, 9, 9, 14, 17, 14, 9, 17, 26, 27, 33, 14, 26, 27, 41, 17, 44, 33, 50, 51, 53, 41, 14, 65, 44, 27, 69, 50, 51, 77, 53, 80, 81, 33, 84, 87, 65, 98, 99, 101, 41, 69, 105, 44, 77, 26, 17, 80, 81, 122, 125, 84, 51, 129, 87, 131, 53, 134, 137, 98, 99, 149, 101, 152, 153

Offset

1,2

Comments

a(n) = (A005244(n) + 1) / A005244(k) for some k.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Hofstadter Sequences

Index entries for Hofstadter-type sequences

Prog

(Haskell)
a139127 1 = 1
a139127 n = head [y | let z = a005244 n + 1,
            y <- reverse $ takeWhile (<= z `div` a020639 z) a005244_list,
            z `mod` y == 0]
-- Reinhard Zumkeller, Feb 26 2013

Crossrefs

Cf. A020639.

Sequence in context: A366975 A267582 A360072 * A239143 A131319 A108962

Adjacent sequences: A139124 A139125 A139126 * A139128 A139129 A139130

Keyword

nonn

Author

Reinhard Zumkeller, Apr 09 2008

Status

approved