|
| |
|
|
A066938
|
|
Primes of the form p*q+p+q, where p and q are primes.
|
|
8
| |
|
|
11, 17, 23, 31, 41, 47, 53, 59, 71, 79, 83, 89, 107, 113, 127, 131, 151, 167, 179, 191, 227, 239, 251, 263, 269, 271, 293, 311, 359, 383, 419, 431, 439, 443, 449, 479, 491, 503, 521, 587, 593, 599, 607, 631, 647, 659, 683, 701, 719, 727, 743, 773, 809, 827
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| For p not equal q either p*q or p+q is odd, so their sum is odd.
The representation is ambiguous, e.g. 2*7+2+7=23=3*5+3+5.
A067432(A049084(a(n))) > 0; complement of A198273 with respect to A000040. [Reinhard Zumkeller, Oct 23 2011]
|
|
|
LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
|
|
|
EXAMPLE
| 59 is in the sequence because 59 = 2 * 19 + 2 + 19.
|
|
|
MATHEMATICA
| nn = 1000; n2 = PrimePi[nn/3]; Select[Union[Flatten[Table[(Prime[i] + 1) (Prime[j] + 1) - 1, {i, n2}, {j, n2}]]], # <= nn && PrimeQ[#] &]
|
|
|
PROG
| (Haskell)
a066938 n = a066938_list !! (n-1)
a066938_list = map a000040 $ filter ((> 0) . a067432) [1..]
-- Reinhard Zumkeller, Oct 23 2011
|
|
|
CROSSREFS
| Cf. A072668, A067432, A072673.
Sequence in context: A145481 A006621 A158913 * A076812 A074207 A063638
Adjacent sequences: A066935 A066936 A066937 * A066939 A066940 A066941
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 24, 2002
|
|
|
EXTENSIONS
| Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 01 2002
|
| |
|
|
