|
Search: id:A074213
|
|
|
| A074213 |
|
Sum of the prime factors of n equals half the sum of the prime factors of n + 1. |
|
+0
1
|
|
| 90, 208, 867, 1161, 1674, 2139, 2295, 2821, 3683, 9675, 10374, 11357, 14823, 17685, 20436, 23750, 23895, 28035, 39039, 39962, 43687, 43813, 47564, 63624, 75615, 79281, 97382
(list; graph; listen)
|
|
|
OFFSET
|
2,1
|
|
|
EXAMPLE
|
The sum of the prime factors of 90 = 2 * 3^2 * 5 is 2 + 3 + 5 = 10; the sum of the prime factors of 91 = 7 * 13 = 20. Hence 90 belongs to the sequence.
|
|
MATHEMATICA
|
p[n_] := Apply[Plus, Transpose[FactorInteger[n]][[1]]]; Select[Range[2, 10^5], 2*p[ # ] == p[ # + 1] &]
|
|
CROSSREFS
|
Sequence in context: A119896 A044422 A044803 this_sequence A027621 A157888 A158490
Adjacent sequences: A074210 A074211 A074212 this_sequence A074214 A074215 A074216
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 18 2002
|
|
|
Search completed in 0.002 seconds
|
