OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..1000
MATHEMATICA
NestList[DivisorSigma[1, #]&, 16, 27] (* Ivan N. Ianakiev, May 02 2015 *)
PROG
(Python)
from itertools import accumulate, repeat # requires Python 3.2 or higher
from sympy import divisor_sigma
A257349_list = list(accumulate(repeat(16, 100), lambda x, _: divisor_sigma(x)))
# Chai Wah Wu, May 02 2015
(PARI) lista(nn) = {print1(v = 16, ", "); for (n=1, nn, v = sigma(v); print1(v, ", "); ); } \\ Michel Marcus, May 02 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 01 2015
STATUS
approved