A051640 a(n) contains the digit b-1 in all bases b from 2 to n.

1, 2, 7, 14, 23, 47, 47, 239, 239, 239, 239, 5927, 13679, 13679, 13679, 57119, 159119, 500399, 500399, 1627919, 2585519, 3694397, 7305479, 17067599, 41126399, 41126399, 41126399, 61483967, 586370399, 589188599, 1278033119, 1278033119, 1278033119, 1278033119, 1278033119

Offset

2,2

Links

Table of n, a(n) for n=2..36.

Example

47 = 101111 (base 2), 1202 (base 3), 233 (base 4), 142 (base 5), 115 (base 6), 65 (base 7), 57 (base 8). Base 2 representation contains digit 1, base 3 representation contains digit 2, base 4 representation contains digit 3, etc., so a(8)=47.

Prog

(Python)
from sympy.ntheory.factor_ import digits
def A051640(n):
    m = 0
    while True:
        for b in range(2, n+1):
            if b-1 not in digits(m, b)[1:]:
                break
        else:
            return m
        m += 1 # Chai Wah Wu, May 18 2020

Crossrefs

Sequence in context: A249852 A324587 A018392 * A119354 A249547 A088207

Adjacent sequences: A051637 A051638 A051639 * A051641 A051642 A051643

Keyword

base,nonn,nice

Author

Jeff Burch, Jun 04 2000

Extensions

More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Jun 12 2000

Definition corrected by Franklin T. Adams-Watters, Apr 10 2006

a(34)-a(36) from Chai Wah Wu, May 18 2020

Status

approved