|
Search: id:A083245
|
|
|
| A083245 |
|
Difference between numbers of related and numbers of unrelated numbers belonging to n: a(n) = A073757[n]-A045763[n] = (n-u[n])-u[n] = n-2.A045763[n] = 2.A073757[n]-n. |
|
+0
3
|
|
| 1, 2, 3, 4, 5, 4, 7, 6, 7, 4, 11, 6, 13, 4, 7, 8, 17, 4, 19, 6, 9, 4, 23, 6, 19, 4, 15, 6, 29, 0, 31, 10, 13, 4, 19, 4, 37, 4, 15, 6, 41, -4, 43, 6, 13, 4, 47, 2, 39, 0, 19, 6, 53, -4, 31, 6, 21, 4, 59, -6, 61, 4, 19, 12, 37, -12, 67, 6, 25, -8, 71, -2, 73, 4, 15, 6, 49, -16, 79, 2, 35, 4, 83, -14, 49, 4, 31, 6, 89, -20, 59, 6, 33, 4, 55, -10, 97, -4
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
FORMULA
|
a(n)=2(A000005[n]+A000010[n]-1)-n
|
|
EXAMPLE
|
n=37, d=2,r=36,u=0, a(37)=2+36-1-0=37>0; primes are fixed points.
n=42, d=8,r=12,u=23,a(42)=8+12-1-23=-4<0, terms of A083244;
n=30, d=8,r=8,u=15, a(30)=0;
n=50, d=6,r=20,u=25,a(50)=0;
there are only 2 cases [n=30,n=50] I obtained below 10^7 when A045763[n]=A073757[n] was satisfied.
|
|
MATHEMATICA
|
Table[2*(DivisorSigma[0, w]+EulerPhi[w]-1)-w, {w, 1, 1000}]
|
|
CROSSREFS
|
Cf. A000005, A000010, A045763, A073757, A083243, A083244, A083246, A020488.
Sequence in context: A135681 A135680 A135682 this_sequence A111610 A119816 A068794
Adjacent sequences: A083242 A083243 A083244 this_sequence A083246 A083247 A083248
|
|
KEYWORD
|
sign
|
|
AUTHOR
|
Labos E. (labos(AT)ana.sote.hu), May 07 2003
|
|
|
Search completed in 0.002 seconds
|
