A338246 Nonpositive values in A117966, in order of appearance and negated.

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

Author

Rémy Sigrist, Oct 18 2020

Keywords

• nonn
• base

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).

Examples

			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, ...
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..9841
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A003462 (fixed points), A117966, A157671, A338245.

Programs

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])))

Formula

a(0) = 0.

a(n) = -A117966(A157671(n)) for any n > 0.

a(n) = n iff n belongs to A003462.