A337535 - OEIS

A337535

For n>1, a(n) is the least base b>2 such that the digits of n in base b contain the digit b-1; a(1)=1.

1, 3, 4, 5, 3, 3, 3, 3, 5, 11, 3, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 3, 4, 4, 3, 3, 3, 3, 37, 19, 3, 4, 41, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 41, 83, 3, 5, 43

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OFFSET

1,2

COMMENTS

The choice b>2 in the name of this sequence comes from the fact that base 2 has the desired property for all n>1.

LINKS

Michel Marcus, Table of n, a(n) for n = 1..10000

EXAMPLE

a(4) = 5 since 4 = 4_5, and 5 is the only base b > 2 with digit b-1.

a(7) = 3 since 7 = 21_3 so containing the digit 2.

PROG

(PARI) isok(n, b) = vecmax(digits(n, b)) == b-1;