cp's OEIS Frontend

A336699 a(n) = A000265(1+A000265(sigma(A000265(n)))), where A000265(k) gives the odd part of k, and sigma is the sum of divisors function.

%I A336699 #16 Mar 27 2022 23:31:49
%S A336699 1,1,1,1,1,1,1,1,7,1,1,1,1,1,1,1,5,7,3,1,1,1,1,1,1,1,3,1,1,1,1,1,1,5,
%T A336699 1,7,5,3,1,1,11,1,3,1,5,1,1,1,29,1,5,1,7,3,5,1,3,1,1,1,1,1,7,1,11,1,9,
%U A336699 5,1,1,5,7,19,5,1,3,1,1,3,1,61,11,11,1,7,3,1,1,23,5,1,1,1,1,1,1,25,29,5,1,13,5,7,1,1
%N A336699 a(n) = A000265(1+A000265(sigma(A000265(n)))), where A000265(k) gives the odd part of k, and sigma is the sum of divisors function.
%C A336699 See the "lacunae" in the scatter plot. - _Antti Karttunen_, Mar 27 2022
%H A336699 Antti Karttunen, <a href="/A336699/b336699.txt">Table of n, a(n) for n = 1..16384</a>
%H A336699 Antti Karttunen, <a href="/A336699/a336699.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%H A336699 Jon Maiga, <a href="http://sequencedb.net/s/A336699">Computer-generated formulas for A336699</a>, Sequence Machine.
%H A336699 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A336699 a(n) = A000265(1+A000265(A000593(n))) = A000265(1+A161942(A000265(n))).
%F A336699 a(n) = A336698(A000265(n)).
%F A336699 From _Antti Karttunen_, Mar 27 2022: (Start)
%F A336699 a(n) = A351565(A000593(n)).
%F A336699 [The following formulas were discovered by Sequence Machine]:
%F A336699 a(n) = A351565(A002131(n)) = A000265(1+A000265(A002131(n))).
%F A336699 a(n) = A336698(1+A322250(n)).
%F A336699 a(n) = A171435(A000593(n)+A082903(n)).
%F A336699 (End)
%o A336699 (PARI)
%o A336699 A000265(n) = (n>>valuation(n,2));
%o A336699 A336699(n) = A000265(1+A000265(sigma(A000265(n))));
%Y A336699 Cf. A000203, A000265, A000593, A002131, A082903, A161942, A171435, A322250, A336698, A336700, A336701, A336844 [= a(A003961(n))], A351565.
%K A336699 nonn,look
%O A336699 1,9
%A A336699 _Antti Karttunen_, Aug 02 2020