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A075380 Rearrangement of natural numbers so that the sum of two neighboring terms is not squarefree. 9
1, 3, 5, 4, 8, 10, 2, 6, 12, 13, 7, 9, 11, 14, 18, 22, 23, 17, 15, 21, 19, 25, 20, 16, 24, 26, 28, 32, 31, 29, 27, 33, 30, 34, 38, 37, 35, 40, 36, 39, 41, 43, 45, 47, 49, 50, 42, 46, 44, 48, 51, 53, 55, 57, 59, 58, 54, 62, 63, 61, 56, 52, 60, 64, 68, 67, 65, 70, 66, 69, 71, 73 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Lexicographically earliest permutation of the natural numbers with the defining property; inverse: A167902; A167901(n) = a(a(n)). [Reinhard Zumkeller, Nov 15 2009]
LINKS
PROG
(PARI) v=[1]; n=1; while(n<100, if(!issquarefree(v[#v]+n)&&!vecsearch(vecsort(v), n), v=concat(v, n); n=0); n++); v \\ Derek Orr, Jun 08 2015
CROSSREFS
Cf. A075381.
Cf. A167903, A121878. [Reinhard Zumkeller, Nov 15 2009]
Sequence in context: A361709 A200700 A356377 * A349374 A248497 A255439
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 22 2002
EXTENSIONS
More terms from David Wasserman, Jan 17 2005
STATUS
approved

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Last modified March 19 06:29 EDT 2024. Contains 370953 sequences. (Running on oeis4.)