|
Search: id:A119728
|
|
|
| A119728 |
|
Primes p such that p+1, p+2, p+3, and p+4 have equal number of divisors. |
|
+0
1
|
|
| 241, 13781, 19141, 21493, 50581, 61141, 76261, 77431, 94261, 95383, 95413, 98101, 104743, 104869, 134581, 141653, 142453, 152629, 153991, 158341, 160933, 165541, 169111, 199831, 201511, 203431, 206551, 229351, 233941, 235111, 253013, 273367
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
EXAMPLE
|
241 is OK since 242, 243, 244, and 245 all have 6 divisors:
{1,2,11,22,121,242},{1,3,9,27,81,243},{1,2,4,61,122,244} and {1,5,7,35,49,245}.
|
|
MATHEMATICA
|
Select[Prime@Range@50000, DivisorSigma[0, #+1]==DivisorSigma[0, #+2]==DivisorSigma[0, #+3]==DivisorSigma[0, #+4]&]
|
|
CROSSREFS
|
Cf. A008329, A049234.
Sequence in context: A007205 A008349 A094732 this_sequence A133327 A001361 A120377
Adjacent sequences: A119725 A119726 A119727 this_sequence A119729 A119730 A119731
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Zak Seidov (zakseidov(AT)yahoo.com), Jul 29 2006
|
|
|
Search completed in 0.002 seconds
|
