|
Search: id:A080863
|
|
|
| A080863 |
|
Numbers n such that spf(n)-2 = spf(n+2), where spf=A020639 (smallest prime factor). |
|
+0
2
|
|
| 25, 55, 85, 115, 145, 175, 203, 205, 235, 265, 295, 325, 355, 385, 413, 415, 445, 475, 505, 535, 565, 595, 623, 625, 655, 685, 715, 745, 775, 805, 833, 835, 865, 895, 925, 955, 985, 1015, 1043, 1045, 1075, 1105, 1135, 1165, 1195, 1225, 1253, 1255, 1285
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
(spf(n+2),spf(n)) are twin prime pairs.
|
|
EXAMPLE
|
16151=31*521, 16151+2=16153=29*557 and (29,31)=(A001359(5), A006512(5)), therefore 16151 is a term: a(625)=16151, A080864(625)=16153.
|
|
CROSSREFS
|
Cf. A080864(n)=a(n)+2, A001359, A006512.
Sequence in context: A123825 A157269 A108166 this_sequence A091214 A036305 A125827
Adjacent sequences: A080860 A080861 A080862 this_sequence A080864 A080865 A080866
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 21 2003
|
|
|
Search completed in 0.002 seconds
|
