|
| |
|
|
A089306
|
|
Smallest prime of the form n + (n+1)+ (n+2)+...+(n+k), or 0 if no such prime exists.
|
|
0
| |
|
|
3, 2, 3, 0, 5, 13, 7, 17, 19, 0, 11, 0, 13, 29, 31, 0, 17, 37, 19, 41, 43, 0, 23, 0, 0, 53, 0, 0, 29, 61, 31, 0, 67, 0, 71, 73, 37, 0, 79, 0, 41, 0, 43, 89, 0, 0, 47, 97, 0, 101, 103, 0, 53, 109, 0, 113, 0, 0, 59, 0, 61, 0, 127, 0, 131, 0, 67, 137, 139, 0, 71, 0, 73, 149, 151, 0, 0
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| If n is prime a(n) = n, If n is not a prime but 2n+1 is a prime then a(n) = 2n+1 else a(n) = 0, as the difference of two triangular numbers is composite if the indices differ by more than 2. r(r+1)/2 - s(s+1)/2 is composite if r-s >2.
|
|
|
CROSSREFS
| Sequence in context: A093347 A134676 A103491 * A086099 A048967 A166592
Adjacent sequences: A089303 A089304 A089305 * A089307 A089308 A089309
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 01 2003
|
|
|
EXTENSIONS
| More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Sep 09 2005
|
| |
|
|
