|
| |
|
|
A137589
|
|
a(n) = first digit of p(n) concatenated with final digit of p(n); where p(n) = n-th prime number.
|
|
0
| |
|
|
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 11, 13, 17, 19, 13, 17, 11, 17, 19, 19, 11, 17, 13, 17, 13, 19, 11, 11, 13, 17, 19, 21, 23, 27, 29, 23, 29, 21, 21, 27, 23, 29, 21, 27, 21, 23, 23, 37, 31, 33, 37, 31, 37, 37, 39, 33
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| The plot of this sequence shows number of primes on the x-axis and the split of primes into 9 groups according to their first digit on the y-axis. The plot of a(n+1)/a(n) oscillates around 1 with decreasing amplitude. Log-periodic growth is seen on the plot of partial sums : b(n)= sum_(i=1..n)(a(i)).
|
|
|
FORMULA
| a(n) = first digit of p(n) concatenated with final digit of p(n); p(n) n-th prime number.
|
|
|
CROSSREFS
| Cf. A000040, A007652, A010879.
Sequence in context: A171041 A094742 A110923 * A052424 A055398 A070159
Adjacent sequences: A137586 A137587 A137588 * A137590 A137591 A137592
|
|
|
KEYWORD
| easy,base,nonn
|
|
|
AUTHOR
| Ctibor O. Zizka (ctibor.zizka(AT)seznam.cz), Apr 26 2008
|
| |
|
|
