OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..20000
MAPLE
a:= proc(n) option remember; `if`(n=0, 0, ((s, t)-> s+
`if`(s<t, t, -t))(a(n-1), numtheory[sigma](n)))
end:
seq(a(n), n=0..80);
MATHEMATICA
nxt[{n_, a_}]:={n+1, If[DivisorSigma[1, n+1]>a, a+DivisorSigma[1, n+1], a- DivisorSigma[ 1, n+1]]}; NestList[nxt, {0, 0}, 70][[All, 2]] (* Harvey P. Dale, May 14 2022 *)
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Alois P. Heinz, Jan 11 2020
STATUS
approved