A379040 Fixed points in A379015.

0, 1, 5, 9, 13, 17, 21, 33, 45, 57, 65, 73, 85, 93, 129, 165, 173, 189, 205, 217, 241, 257, 273, 297, 309, 325, 341, 381, 441, 513, 585, 645, 685, 733, 765, 797, 845, 857, 889, 921, 945, 993, 1025, 1057, 1105, 1129, 1161, 1193, 1205, 1253, 1285, 1317, 1365, 1389

Offset: 1

Author

Darío Clavijo, Dec 14 2024

Keywords

• nonn
• base

Comments

Such points exist when the non-adjacent form representation of n is palindromic.

Links

• Wikipedia, Non-adjacent form.

Crossrefs

Cf. A379015.

Programs

Python

def isok(n):
    E, r = n, 0
    while E:
        if E & 1:
            Zi = 2 - (E & 3)
            E -= Zi
            r += Zi
        E >>= 1
        r <<= 1
    return (r >> 1) == n
print([n for n in range(0,1400) if isok(n)])

Extensions

Leading 0 added by Rémy Sigrist, Dec 28 2024