A386418 a(n) is the number of nondegenerate triangles whose sides are distinct divisors of A386417(n).

2, 1, 5, 4, 6, 4, 2, 8, 3, 23, 1, 3, 19, 8, 14, 1, 17, 11, 1, 2, 3, 10, 2, 7, 57, 14, 1, 11, 13, 37, 9, 2, 8, 12, 1, 45, 4, 79, 3, 3, 14, 2, 7, 9, 5, 3, 45, 35, 11, 12, 4, 6, 1, 106, 62, 2, 8, 33, 1, 34, 3, 4, 41, 1, 3, 57, 4, 3, 50, 2, 6, 7, 25, 12, 16, 14, 30

Offset

1,1

Links

Felix Huber, Table of n, a(n) for n = 1..10000

Example

a(1) = 2 because there are exactly the 2 triangles (2, 3, 4) and (3, 4, 6) whose sides are distinct divisors of A386417(1) = 12.

Maple

A386418:=proc(n)
    option remember;
    local a, k, i;
    if n=1 then
        [12, 2]
    else
        for k from procname(n-1)[1]+1 do
            a:=0;
            for i in combinat[choose](NumberTheory:-Divisors(k), 3) do
                if i[3]<i[1]+i[2] then
                    a:=a+1
                fi
            od;
            if a>0 then
                return [k, a]
            fi
        od
    fi;
end proc;
seq(A386417(n)[2], n=1..77);

Crossrefs

Cf. A027750, A378820, A386417.

Sequence in context: A262219 A249905 A171175 * A176053 A259791 A325771

Adjacent sequences: A386415 A386416 A386417 * A386419 A386420 A386421

Keyword

nonn

Author

Felix Huber, Jul 28 2025

Status

approved