|
Search: id:A136032
|
|
|
| A136032 |
|
Number of prime factors of composite Mersenne numbers. |
|
+0
2
|
|
| 2, 2, 3, 2, 2, 3, 3, 3, 2, 2, 3, 3, 3, 2, 2, 2, 2, 2, 5, 2, 2, 2, 2, 5, 4, 5, 2, 4, 3, 4, 5, 3, 2, 2
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
This sequence is a subset of A088863
|
|
MATHEMATICA
|
a = {}; Do[If[PrimeQ[n] && !PrimeQ[2^n - 1], w = 2^n - 1; c = FactorInteger[w]; d = Length[c]; b = 0; Do[b = b + c[[k]][[2]], {k, 1, d}]; AppendTo[a, b]], {n, 2, 150}]; a
|
|
CROSSREFS
|
Cf. A003260, A016047, A049479, A088863, A136030, A136031.
Sequence in context: A074595 A084126 A135975 this_sequence A140361 A155940 A153095
Adjacent sequences: A136029 A136030 A136031 this_sequence A136033 A136034 A136035
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Artur Jasinski (grafix(AT)csl.pl), Dec 11 2007
|
|
|
Search completed in 0.002 seconds
|
