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A338246
Nonpositive values in A117966, in order of appearance and negated.
4
0, 1, 3, 2, 4, 9, 8, 10, 6, 5, 7, 12, 11, 13, 27, 26, 28, 24, 23, 25, 30, 29, 31, 18, 17, 19, 15, 14, 16, 21, 20, 22, 36, 35, 37, 33, 32, 34, 39, 38, 40, 81, 80, 82, 78, 77, 79, 84, 83, 85, 72, 71, 73, 69, 68, 70, 75, 74, 76, 90, 89, 91, 87, 86, 88, 93, 92, 94
OFFSET
0,3
COMMENTS
This sequence is a self-inverse permutation of the nonnegative integers (the offset has been set to 0 so as to get a permutation).
FORMULA
a(0) = 0.
a(n) = -A117966(A157671(n)) for any n > 0.
a(n) = n iff n belongs to A003462.
EXAMPLE
A117966 = 0, 1, -1, 3, 4, 2, -3, -2, -4, 9, 10, 8, 12, 13, 11, 6, 7, 5, -9, ...
We keep: 0, 1, 3, 2, 4, 9, ...
PROG
(PARI) A117966(n) = subst(Pol(apply(x->if(x == 2, -1, x), digits(n, 3)), 'x), 'x, 3)
print (-select(v -> v<=0, apply(A117966, [0..188])))
CROSSREFS
Cf. A003462 (fixed points), A117966, A157671, A338245.
Sequence in context: A083164 A094962 A338243 * A368225 A371267 A374726
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Oct 18 2020
STATUS
approved