OFFSET
1,2
LINKS
B. Fine, Classification of Finite Rings of Order p^2, Mathematics Magazine, 66(4) (1993), 248-252.
C. R. Fletcher, Rings of Small Order, The Mathematical Gazette, 64(427) (1980), 9-22.
Christof Nöbauer, Numbers of rings on groups of prime power order
Christof Nöbauer, Home page
MATHEMATICA
Clear[phi]; phi[1] = 1; phi[p_, 1] := 8; phi[2, 2] = 66;
phi[2, 3] = 301; phi[3, 2] = 175; phi[n_]:= Module[{aux = FactorInteger[n]}, Product[phi[aux[[i, 1]], aux[[i, 2]]], {i, Length[aux]}]];
CROSSREFS
KEYWORD
nonn,mult,more
AUTHOR
José María Grau Ribas, Feb 14 2021
STATUS
approved