|
Search: id:A079151
|
|
|
| A079151 |
|
Primes p such that p-1 has at most 3 prime factors, counted with multiplicity; i.e. primes p such that bigomega(p+1) = A001222(p+1) <= 3. |
|
+0
5
|
|
| 2, 3, 5, 7, 11, 13, 19, 23, 29, 31, 43, 47, 53, 59, 67, 71, 79, 83, 103, 107, 131, 139, 149, 167, 173, 179, 191, 223, 227, 239, 263, 269, 283, 293, 311, 317, 347, 359, 367, 383, 389, 419, 431, 439, 443, 467, 479, 499, 503, 509, 557, 563, 587, 599, 607, 619, 643
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
EXAMPLE
|
149 is in the sequence because 149-1 = 2*2*37 has 3 prime factors.
|
|
PROGRAM
|
(PARI) s(n) = {sr=0; ct=0; forprime(x=2, n, if(bigomega(x-1) < 4, print1(x" "); sr+=1.0/x; ct+=1; ); ); print(); print(ct" "sr); } \\ Lists primes p<=n such that p-1 has at most 3 prime factors.
|
|
CROSSREFS
|
Cf. A079148, A079150, A079152, A079153.
Sequence in context: A007459 A129944 A152900 this_sequence A005728 A049643 A050437
Adjacent sequences: A079148 A079149 A079150 this_sequence A079152 A079153 A079154
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Cino Hilliard (hillcino368(AT)gmail.com), Dec 27 2002
|
|
|
Search completed in 0.002 seconds
|
