OFFSET
1,1
LINKS
Michel Marcus, Table of n, a(n) for n = 1..255
Michel Marcus, solveBA PARI script
EXAMPLE
For n=1, sigma(1) = 1, so a(1) = 2 since sigma(2)/2 = 3/2, so a(1) = 2.
PROG
(PARI) a(n) = my(q=3*sigma(n, -1)/2, k=1); while(sigma(k, -1) != q, k++); k;
(PARI) a(n) = {my(nv = 3*sigma(n)/(2*n), lim = 1, sv = []); while (#sv == 0, lim *= 10^10; sv = vecsort(solveBA(numerator(nv), denominator(nv), lim))); return (sv[1]); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Nov 26 2021
STATUS
approved