OFFSET
1,1
COMMENTS
a(n) differs from A293183(n) starting at n = 15.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
EXAMPLE
14 is in the sequence since isigma(14) = isigma(15) = 24.
MATHEMATICA
fun[p_, e_] := Module[{ b = IntegerDigits[e, 2]}, m=Length[b]; Product[If[b[[j]]>0, 1+p^(2^(m-j)), 1], {j, 1, m}]]; isigma[1]=1; isigma[n_] := Times @@ fun @@@ FactorInteger[n]; aQ[n_] := isigma[n] == isigma[n+1]; Select[Range[1000], aQ]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Mar 18 2019
STATUS
approved