A368428 Inverse permutation to A368427.

1, 2, 3, 5, 6, 4, 7, 12, 13, 10, 14, 8, 9, 11, 15, 27, 28, 24, 29, 21, 22, 25, 30, 17, 18, 16, 19, 20, 23, 26, 31, 58, 59, 54, 60, 50, 51, 55, 61, 44, 45, 42, 46, 48, 52, 56, 62, 36, 37, 34, 38, 32, 33, 35, 39, 40, 41, 43, 47, 49, 53, 57, 63, 121, 122, 116

Offset: 1

Author

Rémy Sigrist, Dec 24 2023

Keywords

• nonn
• look
• base

Examples

			A368427(67) = 107, so a(107) = 67.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..8191
• Rémy Sigrist, PARI program
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A368427.

Programs

PARI

See Links section.

Python

from itertools import islice
from functools import reduce
def uniq(r): return reduce(lambda u, e: u if e in u else u+[e], r, [])
def A368427gen(): # generator of terms of A368427
    R = [["1"]]
    while R:
        r = R.pop(0)
        yield from map(lambda b: int(b, 2), r)
        if len(r) > 1: R.append(uniq([r[k]+"0" for k in range(1, len(r))]))
        R.append(uniq([r[0]+"0", r[0]+"1"] + [r[k]+"1" for k in range(1, len(r))]))
def agen(): # generator of terms
    adict, n = dict(), 1
    for i, k in enumerate(A368427gen(), 1):
        if k not in adict:
            adict[k] = i
        while n in adict: yield adict[n]; n += 1
print(list(islice(agen(), 66))) # Michael S. Branicky, Dec 24 2023