|
| |
|
|
A066087
|
|
Difference between GCD[Sigma(kernel of n),Phi(kernel of n)] and GCD[Sigma(n),Phi(n)]; kernel = A007947.
|
|
5
| |
|
|
0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, -1, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 2, -2, 0, 0, 2, 1, -1, 0, -4, 0, 4, 0, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -4, -2, 0, 0, 0, 0, -1, 0, 0, -4, 0, 0, 0, 18, 0, -2, 0, 2, 0, 0, 0, 2, 0, -3, 8, -1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 12, -6
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,12
|
|
|
FORMULA
| A009223(n)-A066086(n)= GCD[Sigma(n)], Phi(n)]-GCD[Sigma[A007947(n)], Phi[A007947(n)]]
|
|
|
EXAMPLE
| Frequently but not always zero. At n = 9, Phi[9] = 6, Sigma[9] = 13, GCD[6,13] = 1, kernel[9] = 3, Phi[3] = 2, Sigma[3] = 2, GCD[2,2,] = 2 and GCD[6,13]-GCD[2,2] = -1 = a(9); a(10) = GCD[4,18]-GCD[4,18] = 0, kernel(10) = 10; a(12) = GCD[4,28]-GCD[2,12] = 4-2 = 2, kernel(12) = 6.
|
|
|
CROSSREFS
| A048250, A023900, A000203, A007947, A000010, A009223, A066086.
Sequence in context: A080225 A122841 A060862 * A080224 A010105 A083916
Adjacent sequences: A066084 A066085 A066086 * A066088 A066089 A066090
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Dec 04 2001
|
| |
|
|
