%I A097465
%S A097465 1,3,5,2,7,4,9,11,6,13,8,15,17,10,19,12,23,14,25,16,21,26,29,18,31,20,
%T A097465 27,22,35,24,37,28,33,38,41,30,43,32,39,34,45,47,36,49,40,51,44,53,42,
%U A097465 55,46,57,50,59,48,61,52,63,58,65,54,67,56,69,62,71,60,73,64,75,68,77
%N A097465 a(1) = 1; for n>1, a(n) = smallest positive integer which is not among
earlier terms of sequence, is coprime to a(n-1) and is not equal
to a(n-1) +- 1.
%C A097465 A permutation of the positive integers.
%H A097465 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a>
(listed in lieu of email address)
%e A097465 a(8) = 11 because, among the positive integers not occurring earlier
in the sequence (6,8,10,11,12,...), 11 is the smallest which is coprime
to a(7)=9, is not a(7)+1=10 and is not a(7)-1=8.
%p A097465 A:=proc(n) option remember; local t, S; S:=({$1..1000} minus {seq(A(i),
i=1..n-1)}) minus {A(n-1)-1,A(n-1)+1}; t:=min(S[]); while igcd(A(n-1),
t)>1 do S:=S minus {t}; t:=min(S[]) od; t end: A(1):=1: seq(A(n),
n=1..200); (Mihailovs)
%t A097465 a[1] = 1; a[n_] := a[n] = Block[{t = Table[ a[i], {i, n - 1}], k = 2},
While[k == a[n - 1] - 1 || k == a[n - 1] + 1 || GCD[a[n - 1], k]
!= 1 || Position[t, k] != {}, k++ ]; k]; Table[ a[n], {n, 50}] (from
Robert G. Wilson v Aug 23 2004)
%Y A097465 Cf. A093714, A097467.
%Y A097465 Sequence in context: A113966 A164611 A073897 this_sequence A120683 A079313
A125132
%Y A097465 Adjacent sequences: A097462 A097463 A097464 this_sequence A097466 A097467
A097468
%K A097465 nonn
%O A097465 1,2
%A A097465 Leroy Quet Aug 23 2004
%E A097465 More terms from Alec Mihailovs (alec(AT)mihailovs.com) and Robert G.
Wilson v, Aug 23 2004
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