|
| |
|
|
A090076
|
|
a(n) = prime(n)*prime(n+2).
|
|
5
| |
|
|
10, 21, 55, 91, 187, 247, 391, 551, 713, 1073, 1271, 1591, 1927, 2279, 2773, 3233, 3953, 4331, 4891, 5609, 6059, 7031, 8051, 8989, 9991, 10807, 11227, 12091, 13843, 14803, 17399, 18209, 20413, 20989, 23393, 24613, 26219, 28199, 29893, 31313
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Subsequence of A192133. [Reinhard Zumkeller, Jun 26 2011]
|
|
|
EXAMPLE
| a(5) = prime(5)*prime(7) = 11*17 = 187.
|
|
|
MATHEMATICA
| Table[ Prime[n] Prime[n + 2], {n, 1, 40}] (from Robert G. Wilson v Jan 22 2004)
|
|
|
PROG
| (Mupad) ithprime(i)*ithprime(i+2) $ i = 1..40 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 26 2007
def prime_gaps(n): primegaps = [] nprimes = primes_first_n(n+1) for i in range(2, n+1): primegaps.append(nprimes[i]*nprimes[i-2]) return primegaps print prime_gaps(60) - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 08 2008
|
|
|
CROSSREFS
| Subset of the squarefree semiprimes, A006881. Cf. A006094, A090090.
Sequence in context: A067520 A042309 A048697 * A156592 A045973 A095679
Adjacent sequences: A090073 A090074 A090075 * A090077 A090078 A090079
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Felix Tubiana (fat2(AT)columbia.edu), Jan 21 2004
|
|
|
EXTENSIONS
| Extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 22 2004
|
| |
|
|
