OFFSET
1,1
LINKS
Paolo P. Lava, Table of n, a(n) for n = 1..100
EXAMPLE
Divisors of 376 are 1, 2, 4, 8, 47, 94, 376, 188 and sigma(376) = 720; anti-divisors of 376 are 3, 16, 251 and sigma*(376) = 270.
Therefore 376 is part of the sequence because the digits of 720 are a permutation of the digits of 270.
MAPLE
with(numtheory); P:= proc(i) local a, b, c, j, k, n, ok, p;
for n from 3 to i do b:=[]; c:=[];
k:=0; j:=n; while j mod 2<>1 do k:=k+1; j:=j/2; od;
a:=sigma(2*n+1)+sigma(2*n-1)+sigma(n/2^k)*2^(k+1)-6*n-2;
while a>0 do b:=[op(b), a mod 10]; a:=trunc(a/10); od; a:=sigma(n);
while a>0 do c:=[op(c), a mod 10]; a:=trunc(a/10); od;
if nops(b)=nops(c) then b:=sort(b); c:=sort(c); b:=b-c; ok:=1;
for j from 1 to nops(b) do if b[j]<>0 then ok:=0; break; fi; od;
if ok=1 then print(n); fi; fi; od; end; P(10^6);
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
Paolo P. Lava, Oct 23 2013
STATUS
approved