|
| |
|
|
A101294
|
|
Numbers n such that omega(n-2) = omega(n-1) = omega(n) = omega(n+1) = omega(n+2).
|
|
1
| |
|
|
56, 93, 94, 117, 143, 144, 145, 146, 160, 207, 214, 215, 216, 217, 297, 303, 325, 326, 327, 393, 537, 687, 723, 801, 1137, 1347, 1467, 1537, 1713, 1943, 1983, 2103, 2217, 2304, 2305, 2306, 2427, 2643, 2666, 2716, 3867, 3914, 4413
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
EXAMPLE
| 143 is in the sequence because it has two unique prime factors (11 and 13), the same number as its two nearest neighbors on both sides (141 has 3 and 47, 142 has 2 and 71, 144 has 2 and 3 and 145 has 5 and 29).
|
|
|
MATHEMATICA
| For[i=2, i<10000, If[And[Length[FactorInteger[i-2]]==Length[FactorInteger[i]], Length[FactorInteger[i-1]]==Length[FactorInteger[i]], Length[FactorInteger[i+1]]==Length[FactorInteger[i]], Length[FactorInteger[i+2]]==Length[FactorInteger[i]]], Print[i]]; i++ ]
|
|
|
CROSSREFS
| Cf. A001221, A101932.
Sequence in context: A043938 A104394 A101935 * A039534 A063347 A054891
Adjacent sequences: A101291 A101292 A101293 * A101295 A101296 A101297
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| N. Fernandez (primeness(AT)borve.org), Dec 21 2004
|
|
|
EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), Mar 17 2007
|
| |
|
|
