OFFSET
1,3
COMMENTS
a(n>1) contains all positive integers exactly once.
FORMULA
MATHEMATICA
z = 100; prisigs = Table[If[n == 1, {}, Sort[Last /@ FactorInteger[n]]], {n, z}];
exps = Table[Count[Take[prisigs, n], prisigs[[n]]], {n, z}]; (* A064839 *)
Table[2^(exps[[n]] - 1) (2 Times @@ Prime[prisigs[[n]]] - 3), {n, z}]
CROSSREFS
KEYWORD
sign
AUTHOR
Friedjof Tellkamp, Apr 20 2024
STATUS
approved