A371812 Number of different ways A329383(n) is Brazilian.

0, 1, 2, 3, 4, 5, 7, 8, 9, 11, 14, 15, 16, 17, 19, 23, 29, 31, 35, 39, 41, 44, 47, 49, 52, 59, 63, 71, 79, 83, 89, 95, 99, 107, 111, 119, 127, 143, 159, 167, 179, 190, 191, 199, 215, 223, 239, 251, 255, 287, 299, 319, 335, 359, 383, 399, 431, 447, 479, 503

Offset

1,3

Comments

Or number of bases from 2 to n-2 in which the highly Brazilian number A329383(n) is a repdigit number.

Note that from a(26) to a(75) except for a(31) and a(42), a(n) = 4k-1 for some k.

Links

Daniel Mondot, Table of n, a(n) for n = 1..91

Example

A329383(2) = 7 is Brazilian in only 1 base below 6 (base 2), so a(2) = 1.
A329383(3) = 15 is Brazilian in 2 bases below 14 (bases 2, 4), so a(3) = 2.

Prog

(C)
#include <stdio.h>
FILE *fi;
unsigned int cnt, d, line;
long unsigned base, k, ln;
void main()
{
    fi = fopen("b329383.txt", "r");
    for(;; )
    {
        if (fscanf(fi, "%u %lu", &line, &ln) < 2) break;
        for (cnt=0, base=2; base<ln-1; ++base)
        {
            if (d = ln % base)
            for (k = ln / base; k; )
            {
                if ((k % base) != d) break;
                if ((k /= base) == 0) ++cnt;
            }
        }
        printf("%u %u\n", line, cnt);
    }
    fclose(fi);
}

Crossrefs

Cf. A329383, A284758, A242397.

Sequence in context: A340815 A280619 A282136 * A153730 A140691 A328668

Adjacent sequences: A371809 A371810 A371811 * A371813 A371814 A371815

Keyword

nonn,base

Author

Daniel Mondot, Apr 06 2024

Status

approved