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%I #20 Nov 19 2023 10:46:24
%S 1,1,0,1,0,1,0,1,1,1,0,1,0,0,0,1,0,1,0,1,1,1,0,1,1,0,1,1,0,1,0,1,1,0,
%T 0,1,0,0,0,1,0,1,0,0,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,0,0,1,0,1,0,1,
%U 0,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,1,0,0,1,0,1,1,1,1,0,0,1,0,1,0,1,0,1
%N a(n) = 1 if gpf(n) < gpf(n+1), otherwise 0, where gpf = A006530 (greatest prime factor).
%C Equivalently, a(n) = 1 iff A061395(n+1) > A061395(n), otherwise a(n) = 0. - _Giovanni Teofilatto_, Jan 03 2008
%H Amiram Eldar, <a href="/A087429/b087429.txt">Table of n, a(n) for n = 1..10000</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = A057427(1+A057427(A070221(n))).
%F a(p-1)=1 and a(p)=0 for primes p.
%F a(A070089(n)) = 1, a(A070087(n)) = 0, a(A087430(n)) = 0.
%t Join[{1}, Table[If[PrimePi[FactorInteger[n + 1][[ -1, 1]]] > PrimePi[FactorInteger[n][[ -1, 1]]], 1, 0], {n, 2, 90}]] (* _Stefan Steinerberger_, Jan 06 2008 *)
%t If[#[[1]]<#[[2]],1,0]&/@Partition[FactorInteger[#][[-1,1]]&/@Range[120],2,1] (* _Harvey P. Dale_, Nov 19 2023 *)
%Y Characteristic function of A070089.
%Y Cf. A006530, A057427, A061395, A070087, A070221, A087430.
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, Sep 02 2003
%E Edited by _N. J. A. Sloane_, Jul 01 2008, at the suggestion of _R. J. Mathar_
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