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A319694 Product of A078899(x) for all x encountered when map x -> A252463(x) is iterated, starting from x = A252463(n); a(1) = 1. 3

%I #9 Nov 21 2018 20:31:42

%S 1,1,1,1,1,1,1,2,2,1,1,2,1,1,2,6,1,6,1,2,2,1,1,8,6,1,6,2,1,6,1,24,2,1,

%T 6,30,1,1,2,8,1,6,1,2,8,1,1,48,30,30,2,2,1,42,6,8,2,1,1,36,1,1,8,120,

%U 6,6,1,2,2,30,1,240,1,1,30,2,30,6,1,56,24,1,1,36,6,1,2,8,1,64,30,2,2,1,6,432,1,210,8,270,1,6,1,8,36

%N Product of A078899(x) for all x encountered when map x -> A252463(x) is iterated, starting from x = A252463(n); a(1) = 1.

%H Antti Karttunen, <a href="/A319694/b319694.txt">Table of n, a(n) for n = 1..16384</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%o (PARI)

%o up_to = 16384;

%o ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om,invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om,invec[i],(1+pt))); outvec; };

%o A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);

%o v078899 = ordinal_transform(vector(up_to,n,A006530(n)));

%o A078899(n) = v078899[n];

%o A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};

%o A252463(n) = if(!(n%2),n/2,A064989(n));

%o A319694(n) = { my(m=1); while(1<(n=A252463(n)), m *= A078899(n)); (m); };

%Y Cf. A005940, A078899, A252463.

%Y Cf. also A319689.

%K nonn

%O 1,8

%A _Antti Karttunen_, Nov 21 2018

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Last modified April 25 06:14 EDT 2024. Contains 371964 sequences. (Running on oeis4.)