|
| |
|
|
A074953
|
|
Numbers equidistant from consecutive twin prime pairs.
|
|
1
| |
|
|
5, 9, 15, 24, 36, 51, 66, 87, 105, 123, 144, 165, 186, 195, 213, 234, 255, 276, 297, 330, 384, 426, 447, 492, 546, 585, 609, 630, 651, 735, 816, 825, 843, 870, 951, 1026, 1041, 1056, 1077, 1122, 1191, 1254, 1284, 1296, 1311, 1374, 1440
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
FORMULA
| a(n)=Sum_{x=nth greater of twin primes..(n+1)th lesser of twin primes}-(-1)^x*x
|
|
|
EXAMPLE
| The twin prime pairs are (3,5), (5,7), (11,13), (17,19), etc. a(n) is equidistant from the higher prime in the n-th pair and the lower prime in the (n+1)th pair. E.g. a(2) is the mean of 7 and 11, which is 9.
|
|
|
CROSSREFS
| Cf. A001359, A006512.
Sequence in context: A075343 A102176 A025005 * A023498 A062516 A075133
Adjacent sequences: A074950 A074951 A074952 * A074954 A074955 A074956
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| N. Fernandez (primeness(AT)borve.org), Oct 05 2002
|
|
|
EXTENSIONS
| Formula addited by Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jul 14 2009
|
| |
|
|
