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%I #13 Jul 10 2024 02:59:10
%S 0,0,1,0,0,1,3,3,4,0,0,1,0,0,1,3,3,4,9,9,10,9,9,10,12,12,13,0,0,1,0,0,
%T 1,3,3,4,0,0,1,0,0,1,3,3,4,9,9,10,9,9,10,12,12,13,27,27,28,27,27,28,
%U 30,30,31,27,27,28,27,27,28,30,30,31,36,36,37,36
%N a(n) is the least term t of A005836 such that n - t also belongs to A005836.
%C To compute a(n): in the ternary expansion of n, replace 1's by 0's and 2's by 1's.
%H Rémy Sigrist, <a href="/A374362/b374362.txt">Table of n, a(n) for n = 0..6561</a>
%F a(n) = A374361(n, 0).
%F a(n) = n - A374363(n).
%F a(n) >= 0 with equality iff n belongs to A374361.
%F a(n) = A005836(1 + A289814(n)).
%e The first terms, in decimal and in ternary, are:
%e n a(n) ter(n) ter(a(n))
%e -- ---- ------ ---------
%e 0 0 0 0
%e 1 0 1 0
%e 2 1 2 1
%e 3 0 10 0
%e 4 0 11 0
%e 5 1 12 1
%e 6 3 20 10
%e 7 3 21 10
%e 8 4 22 11
%e 9 0 100 0
%e 10 0 101 0
%e 11 1 102 1
%e 12 0 110 0
%e 13 0 111 0
%e 14 1 112 1
%e 15 3 120 10
%o (PARI) a(n) = fromdigits(apply(d -> [0, 0, 1][1+d], digits(n, 3)), 3)
%o (Python)
%o from gmpy2 import digits
%o def A374362(n): return int(digits(n,3).replace('1','0').replace('2','1'),3) # _Chai Wah Wu_, Jul 09 2024
%Y Cf. A005836, A289814, A374361.
%K nonn,base
%O 0,7
%A _Rémy Sigrist_, Jul 06 2024