OFFSET
1,1
EXAMPLE
114 is in the sequence since it is the lesser of the amicable pair (114, 126): susigma(114) = susigma(126) = 114 + 126.
MATHEMATICA
f[p_, e_] := (p^Floor[(e + 1)/2] - 1)/(p - 1) + p^e; s[n_] := If[n == 1, 1, Times @@ (f @@@ FactorInteger[n])] - n; seq = {}; Do[n = s[m]; If[n > m && s[n] == m, AppendTo[seq, m]], {m, 1, 1000000}]; seq
PROG
(PARI) susigma(n) = {my(f = factor(n)); for (k=1, #f~, my(p=f[k, 1], e=f[k, 2]); f[k, 1] = (p^((e+1)\2) - 1)/(p-1) + p^e; f[k, 2] = 1; ); factorback(f); } \\ A322485
isok(n) = my(m=susigma(n)-n); (m > n) && (susigma(m) == n + m); \\ Michel Marcus, Dec 15 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Dec 14 2018
STATUS
approved