Near Multiperfects
Near-Multiperfects
A near-multiperfect has near-integer abundancy , i.e. , the sum of its
divisors leaves a small remainder when divided by some small multiple .
More specifically , a near-multiperfect is defined as any natural n ,
with :
sum-of-divisors ( n ) = k * n + r
abs ( r ) <= loge ( n )
loge is the log to the base e = natural log = the Napierian logarithm .
This definition includes the multiperfect .
A proper near-multiperfect is a near-multiperfect which is not
multiperfect .
Least Near-Multiperfects
This list of the least near-multiperfects excludes
a) primes ,
b) powers of 2 and
c) naturals of the form 6 times a prime .
n r
6 0
10 -2
20 2
28 0
70 4
88 4
104 2
110 -4
120 0
136 -2
152 -4
464 2
496 0
592 -6
650 2
672 0
884 -4
1155 -6
1888 4
1952 2
2144 -4
4030 4
5830 4
8128 0
8384 -4
8925 6
11096 8
17816 8
18632 -4
18904 -8
30240 0
32128 4
32445 6
32760 0
32896 -2
33664 -8
45356 8
70564 -8
77744 8
85936 -8
91388 8
100804 -8
116624 -4
128768 8
130304 2
133376 -10
244036 -11
254012 8
388076 8
391612 -8
430272 12
442365 6
518656 10
521728 4
522752 2
523776 0
527872 -8
528896 -10
1090912 -8
1848964 4
2087936 8
2102272 -6
2178540 0
2291936 8
8378368 4
8382464 2
8394752 -4
9928792 16
11547352 16
12026888 -16
13174976 8
13192768 -16
15370304 -4
16102808 -16
17619844 -8
17999992 16
23569920 0
26347688 -16
29322008 -16
29465852 8
33501184 12
33550336 0
33653888 -16
35021696 8
45335936 8
45532800 0
73995392 -4
89283592 16
120888092 8
134094848 14
134193152 2
142990848 0
159030135 18
169371008 -16
173482552 16
173631608 -16
184773312 12
260378492 8
293947648 -16
361702144 16
381236216 8
459818240 0
536559616 18
536920064 -4
537051136 -12
537116672 -16
624032630 20
775397948 8
815634435 -6
883927808 -16
1081850752 16
1113445430 20
1379454720 0
1476304896 0
1550860550 20
1631268870 -18
1845991216 16
2146926592 16
2146992128 14
2147516416 -2
2147581952 -4
2147713024 -8
2147975168 -16
2493705728 -16
2586415095 18
3381872252 8
3915380170 -20
4856970752 8
5556840416 -16
6077111050 -20
6800228816 8
6800695312 -8
8589082624 12
8589344768 8
8589869056 0
9796360330 -20
10828121356 -20
11097907192 16
12985220152 16
13092865928 -16
14182439040 0
21818579968 16
31998395520 0
34356723712 22
34357510144 16
34358296576 10
34359083008 4
34360131584 -4
34360655872 -8
34360918016 -10
42783299288 -16
count = 151
The multiperfects have remainder , r = 0 .
This list is complete through
43279999099 .
The near-multiperfects are
sequence A117349
in Neil J. A. Sloane's On-Line Encyclopedia of Integer Sequences .
Walter Nissen
2008-01-21