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A095689 Permutation of natural numbers, inverse permutation to A094870. 2
1, 2, 4, 3, 5, 6, 8, 7, 10, 9, 14, 12, 11, 13, 18, 16, 15, 20, 26, 22, 21, 17, 19, 24, 23, 25, 28, 27, 29, 38, 32, 31, 33, 36, 40, 30, 39, 35, 34, 44, 37, 43, 45, 41, 50, 47, 49, 42, 52, 46, 56, 48, 58, 51, 66, 53, 55, 54, 59, 61, 57, 64, 60, 63, 67, 78, 68, 62, 70, 65, 77, 75 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

2n/3 < a(n) <= 8n/3 (P. Hegarty).

Conjecture: lim_{n->infinity} a(n)/n = 1 (P. Hegarty).

LINKS

Carl R. White, Table of n, a(n) for n = 1..9660

Peter Hegarty, Permutations avoiding arithmetic patterns, The Electronic Journal of Combinatorics, 11 (2004), #R39.

EXAMPLE

a(3)=4 because A094870(4)=3.

MAPLE

A:=proc(n) option remember; local t, S, i; S:={$1..300} minus {seq(A(i), i=1..n-1)}; t:=min(S[]); i:=1; while i<floor((n+1)/2) do if t-A(n-i)=A(n-i)-A(n-2*i) then S:=S minus {t}; t:=min(S[]); i:=1 else i:=i+1 fi od; t end: A(1):=1: L:=[seq(A(n), n=1..200)]: a:=n-> if member(n, L, 'p') then p else 0 fi: seq(a(n), n=1..194);

CROSSREFS

Cf. A094870.

Sequence in context: A095690 A094870 A075618 * A083194 A105366 A077156

Adjacent sequences: A095686 A095687 A095688 * A095690 A095691 A095692

KEYWORD

easy,nonn

AUTHOR

Alec Mihailovs (alec(AT)mihailovs.com), Jul 05 2004

STATUS

approved

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Last modified January 29 04:47 EST 2023. Contains 359915 sequences. (Running on oeis4.)