OFFSET
1,1
COMMENTS
a(n) = n if n is prime.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
EXAMPLE
a(1) = 6 because 6 = 2*3 and 3 - 2 = 1.
MATHEMATICA
dgpd[n_]:=With[{fi=FactorInteger[n][[;; , 1]]}, fi[[-1]]-Total[Most[fi]]]; Join[{6}, With[{tbl=Table[ {n, dgpd[n]}, {n, 2500}]}, Table[SelectFirst[tbl, #[[2]]==k&], {k, 2, 60}]][[;; , 1]]] (* Harvey P. Dale, Jul 29 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Apr 09 2012
STATUS
approved