A376045 Complement of A325112.

3, 6, 9, 12, 13, 15, 16, 18, 19, 21, 23, 24, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 42, 43, 45, 46, 48, 49, 51, 53, 54, 56, 57, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 72, 73, 75, 76, 78, 79, 81, 83, 84, 86, 87, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 102, 103, 105, 106, 108

Offset

1,1

Comments

Numbers missing from A325112.

Equivalently, numbers whose decimal expansion has a subsequence which is divisible by 3.

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Prog

(Python)
from itertools import combinations
def A376045(n):
    def f(x):
        c, l = 0, len(str(x))
        for i in range(l):
            k = 10**i
            for j in (1, 2, 4, 5, 7, 8):
                if j*k<=x:
                    c += 1
        for a in combinations((10**i for i in range(l)), 2):
            for b in ((1, 1), (1, 4), (1, 7), (2, 2), (2, 5), (2, 8), (4, 1), (4, 4), (4, 7), (5, 2), (5, 5), (5, 8), (7, 1), (7, 4), (7, 7), (8, 2), (8, 5), (8, 8)):
                if a[0]*b[0]+a[1]*b[1] <= x:
                    c += 1
        return n+c
    m, k = n, f(n)
    while m != k: m, k = k, f(k)
    return m # Chai Wah Wu, Sep 10 2024

Crossrefs

Cf. A325112.

Sequence in context: A285402 A153403 A336341 * A257220 A092452 A230215

Adjacent sequences: A376042 A376043 A376044 * A376046 A376047 A376048

Keyword

nonn,base

Author

N. J. A. Sloane, Sep 09 2024

Status

approved