cp's OEIS Frontend

A302847 Permutation of natural numbers: a(1) = 1; for n > 1, a(n) = A064989(2+A003961(n-1)).

%I A302847 #14 Dec 23 2024 14:53:45
%S A302847 1,2,3,5,7,4,13,11,23,8,19,6,43,17,15,31,79,10,35,9,33,34,37,29,131,
%T A302847 26,47,113,97,14,103,22,75,61,53,73,223,41,67,46,181,12,163,25,65,106,
%U A302847 83,21,217,74,139,89,87,59,253,58,209,44,51,20,313,38,109,271,533,49,193,71,167,50,229,18,673,16,27,187,119,69,251,39,563,238,127,55,335,24
%N A302847 Permutation of natural numbers: a(1) = 1; for n > 1, a(n) = A064989(2+A003961(n-1)).
%H A302847 Antti Karttunen, <a href="/A302847/b302847.txt">Table of n, a(n) for n = 1..20000</a>
%H A302847 David Newman, et al., <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2018-January/018239.html">New sequences from old, Discussion on SeqFan-mailing list</a>, January 2018.
%H A302847 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%H A302847 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F A302847 a(1) = 1; for n > 1, a(n) = A064989(2+A003961(n-1)).
%F A302847 a(1) = 1; for n > 1, a(n) = A064216(1+A048673(n-1)).
%o A302847 (PARI)
%o A302847 A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
%o A302847 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 A302847 A302847(n) = if(1==n,n,A064989(2+A003961(n-1)));
%Y A302847 Cf. A302848 (inverse).
%Y A302847 Cf. A003961, A048673, A064216, A064989.
%Y A302847 Cf. also A297165, A302849.
%K A302847 nonn
%O A302847 1,2
%A A302847 _Antti Karttunen_, Apr 26 2018