|
Search: id:A099073
|
|
|
| A099073 |
|
Numbers n such that the concatenation of the first n-1 odd primes in decreasing order is prime. |
|
+0
2
|
| |
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
A100003(n)=prime(a(n)). Next term is greater than 4500 and the prime corresponding to the next term has more than 21000 digits. Number of digits of primes corresponding to the six known terms of the sequence are respectively 1,2,9,43,198 & 4202. There is no known prime formed by concatenation of the first n odd primes with increasing order for 1<n<2250.
|
|
LINKS
|
C. Rivera, Primes by Listing.
|
|
EXAMPLE
|
7 is in the sequence because the first 6 odd primes are 3,5,7,11,13,17 and 17.13.11.7.5.3 is prime (dot between numbers means concatenation).
|
|
MATHEMATICA
|
Do[If[PrimeQ[(v={}; Do[v=Join[v, IntegerDigits[Prime[n-j+1]]], {j, n-1}]; FromDigits[v])], Print[n]], {n, 2, 4500}]
|
|
CROSSREFS
|
Cf. A046035, A099070, A099071.
Sequence in context: A006892 A102710 A048824 this_sequence A129724 A094697 A095910
Adjacent sequences: A099070 A099071 A099072 this_sequence A099074 A099075 A099076
|
|
KEYWORD
|
base,more,nonn,nice
|
|
AUTHOR
|
Farideh Firoozbakht (mymontain(AT)yahoo.com), Nov 06 2004
|
|
|
Search completed in 0.002 seconds
|
