|
Search: id:A156761
|
|
|
| A156761 |
|
Tribonacci primes that are also primes when their digits are reversed. |
|
+0
1
|
| |
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
This is to A115347 as Fibonacci numbers A000045 are to A000213 tribonacci numbers. Except for palidromatic tribonacci numbers {3, 5, ...} these are tribonacci emirps, A000213 INTERSECTION A006567.
The next term, if it exists, is greater than A000213(10000). [From Dmitry Kamenetsky (dkamen(AT)rsise.anu.edu.au), Mar 03 2009]
|
|
FORMULA
|
{p such that p is in A000040 and p is in A000213 and R(p) = A004086(p) is in A000040} = {p such that p is in A056816 and R(p) = is in A000040}.
|
|
EXAMPLE
|
a(5) = 1201 because 1201 is prime, and is the 13th tribonacci number A000213(13), and R(1201) = A004086(1201) = 1021 is also prime. a(6) = 128199521 = the 10th tribonacci prime A056816(10), and its digital reverse 125991821 is also prime.
|
|
CROSSREFS
|
Cf. A000040, A000045, A000213, A004086, A006567, A056816, A115347.
Sequence in context: A103149 A007802 A056816 this_sequence A151261 A148504 A148505
Adjacent sequences: A156758 A156759 A156760 this_sequence A156762 A156763 A156764
|
|
KEYWORD
|
more,nonn,base
|
|
AUTHOR
|
Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 15 2009
|
|
|
Search completed in 0.002 seconds
|
