|
| |
|
|
A121390
|
|
Sequence generated by the recurrence below begins with exactly seven primes.
|
|
1
| |
|
|
2, 8607769, 25823309, 222281113118699, 5740034091209256896999, 1275901167133279185594625154673899999, 7323716196358702385046852882006552347670105360888299999999
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
COMMENTS
| This sequence has the smallest value of a(1) for a(0) = 2 and this recurrence such that the first seven terms are primes. The first composite term is too large to include. Note also that each a(n) has Fibonacci(n) trailing 9s (see A121389).
|
|
|
FORMULA
| a(0) = 2; a(1) = 8607769; a(n) = a(n-2)*a(n-1) + a(n-2) + a(n-1).
|
|
|
EXAMPLE
| a(2) = 25823309 = 2*8607769 + 2 + 8607769 and is prime.
|
|
|
CROSSREFS
| Cf. A000045, A063896, A121389.
Sequence in context: A137601 A158347 A157991 * A170997 A157992 A135235
Adjacent sequences: A121387 A121388 A121389 * A121391 A121392 A121393
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jul 26 2006
|
| |
|
|
