|
| |
|
|
A131205
|
|
a(n) = a(n-1) + a(floor(n/2)) + a(ceiling(n/2)).
|
|
2
| |
|
|
1, 3, 7, 13, 23, 37, 57, 83, 119, 165, 225, 299, 393, 507, 647, 813, 1015, 1253, 1537, 1867, 2257, 2707, 3231, 3829, 4521, 5307, 6207, 7221, 8375, 9669, 11129, 12755, 14583, 16613, 18881, 21387, 24177, 27251, 30655, 34389, 38513, 43027, 47991
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Contribution from Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 16 2009: (Start)
Let M = an infinite lower triangular matrix with (1, 3, 4, 4, 4,...) in
every column shifted down twice, with the rest zeros:
1;
3, 0;
4, 1, 0;
4, 3, 0, 0;
4, 4, 1, 0, 0;
4, 4, 3, 0, 0, 0;
...
A131205 = Lim_{n->inf.} M^n, the left-shifted vector considered as a sequence. (End)
The subsequence of primes in this sequence begins with 5 in a row: 3, 7, 13, 23, 37, 83, 647, 1867, 2707, 88873, 388837, 655121, 754903, 928621, 1062443. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 25 2010]
|
|
|
LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
|
|
|
FORMULA
| Partial sums of A000123: (1, 2, 4, 6, 10, 14, 20, 26,...). - Gary W. Adamson (qntmpkt(AT)yahoo.com), Oct 26 2007
|
|
|
CROSSREFS
| Cf. A033485, A000123.
Cf. A131205.
Sequence in context: A103116 A075321 A164787 * A058682 A081995 A053599
Adjacent sequences: A131202 A131203 A131204 * A131206 A131207 A131208
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 22 2007
|
|
|
EXTENSIONS
| Subsequence of primes. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 25 2010]
|
| |
|
|
