1,3

Seiichi Manyama, Table of n, a(n) for n = 1..10000

k that satisfies sigma(k) = 12 is 6 or 11. d(6) = 4 and d(11) = 2. So a(12) = 4.

(PARI) a(n) = my(m=0); for(k=1, n, if(sigma(k)==n, m=max(m, numdiv(k)))); m;

Cf. A000005, A000203, A054973, A057637, A085790, A299762.

Sequence in context: A328903 A143539 A249063 * A099307 A256750 A228430

Adjacent sequences: A341876 A341877 A341878 * A341880 A341881 A341882

nonn,easy

Seiichi Manyama, Feb 22 2021

approved