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A060030 If the numbers a(1)...a(n) contain a hole, then a(n+1) is the largest hole; otherwise a(n+1) = a(n-1) + a(n). 3
1, 2, 3, 5, 4, 9, 8, 7, 6, 13, 12, 11, 10, 21, 20, 19, 18, 17, 16, 15, 14, 29, 28, 27, 26, 25, 24, 23, 22, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A self-inverse permutation of the natural numbers: a(a(n)) = n and  a(n) <> n for n > 3. [Reinhard Zumkeller, Apr 29 2012]

LINKS

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

Index entries for sequences that are permutations of the natural numbers

PROG

(Haskell)

import Data.List (delete)

a060030 n = a060030_list !! (n-1)

a060030_list = 1 : 2 : f 1 2 [3..] where

   f u v ws = y : f v y (delete y ws) where

     y = if null xs then u + v else last xs

     xs = takeWhile (< v) ws

-- Reinhard Zumkeller, Apr 29 2012

CROSSREFS

See A060482 for successive records, A027383 for the final hole-filling values, A016116 for the difference between top and bottom of downward subsequences, A052551 for number of terms in downward subsequences.

Cf. A060000, A000045.

Sequence in context: A330615 A302850 A338253 * A081025 A329811 A245607

Adjacent sequences:  A060027 A060028 A060029 * A060031 A060032 A060033

KEYWORD

easy,nice,nonn

AUTHOR

William Nelles (wnelles(AT)flashmail.com), Mar 17 2001

EXTENSIONS

Offset corrected by Reinhard Zumkeller, Apr 29 2012

STATUS

approved

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Last modified June 13 00:57 EDT 2021. Contains 344980 sequences. (Running on oeis4.)