cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A348369 Number of ways A328596(n) (the reversed binary expansion is an aperiodic necklace) can be expressed as sum A328596(k) + A328596(m) with 0 < k,m < n. The cases A328596(k) + A328596(m) and A328596(m) + A328596(k) are considered equal.

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%I A348369 #45 May 06 2022 13:13:51
%S A348369 0,1,1,1,2,2,2,3,2,3,4,3,4,6,3,5,5,5,5,7,5,5,9,4,6,5,8,7,9,9,7,8,10,9,
%T A348369 9,13,6,8,8,9,15,7,10,8,14,10,12,10,11,13,13,14,14,15,16,13,14,15,15,
%U A348369 18,14,18,16,16,22,10,9,12,12,10,24,10,16,9,21,14,20,12
%N A348369 Number of ways A328596(n) (the reversed binary expansion is an aperiodic necklace) can be expressed as sum A328596(k) + A328596(m) with 0 < k,m < n. The cases A328596(k) + A328596(m) and A328596(m) + A328596(k) are considered equal.
%C A348369 Conjecture: The only zero in this sequence is a(1). A348268 maps all terms of A328596 bijective to primes. Let P be this bijection between Lyndon words and primes and P' its inverse. Then for each prime q, there exist primes r and s such that q = P(P'(r) + P'(s)). If we were to define a table T(m,n) which encodes the sum q + 1 = (A000040(m) + A000040(n)), then q = P(P'(A000040(m)) + P'(A000040(n))) would be a permutation of this table; this connects this conjecture to Goldbach's conjecture.
%C A348369 All reversed binary expansions of powers of two are Lyndon words. All reversed binary expansions of numbers of the form 2*(2^m - 1) are Lyndon words, too. 2*(2^m - 1) + 2 is again a power of 2. Every positive integer can be expressed as a sum of powers of 2. From this we can conclude that it is always possible to compose terms of A328596(n) (n > 1), as a sum of terms of A328596. This would require at least 2 or more such terms.
%H A348369 Thomas Scheuerle, <a href="/A348369/a348369.svg">a(1)..a(4000)</a> (Both axes are logarithmic and denote 2^x and 2^y. It appears that this sequence is self-similar, with an irrational exponent.)
%e A348369 A328596(5) = A328596(2) + A328596(4) = A328596(3) + A328596(3) -> a(5) = 2.
%e A348369 .
%e A348369 Table A: A348268(A348268^-1(m) + A348268^-1(n))
%e A348369       2   3   5   7
%e A348369   -----------------
%e A348369   2| (3)  4   6   8   prime numbers are marked by ()
%e A348369   3|  4  (5) (7)(11)
%e A348369   5|  6  (7)(11)  9
%e A348369   7|  8 (11)  9 (13)
%e A348369 .
%e A348369 Table B: m + n
%e A348369       2   3   5   7
%e A348369   -----------------
%e A348369   2| (4)  5   7   9   prime numbers + 1 are marked by ()
%e A348369   3|  5  (6) (8) 10
%e A348369   5|  7  (8) 10 (12)
%e A348369   7|  9  10 (12)(14)
%e A348369 .
%e A348369 Table B is a permutation of Table A + 1.
%Y A348369 Cf. A328596, A348268, A348352.
%K A348369 nonn
%O A348369 1,5
%A A348369 _Thomas Scheuerle_, Oct 15 2021