|
| |
|
|
A034818
|
|
Concatenations C1 and C2 and C3 are all prime (see the comment lines).
|
|
0
|
|
|
|
657, 4929, 10647, 18291, 20907, 22653, 27381, 28053, 28671, 42471, 48441, 57363, 69651, 79569, 89853, 93261, 95967, 101283, 110763, 119481, 128613, 145719, 149409, 174993, 201417, 204861, 205329, 221883, 248391, 269199, 272799, 293451
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,1
|
|
|
COMMENTS
|
C1 = 'nextprime(n) followed by n'
C2 = 'n followed by prevprime(n)'
C3 = 'nextprime(n) followed by n followed by prevprime(n)'
|
|
|
LINKS
|
Table of n, a(n) for n=0..31.
|
|
|
EXAMPLE
|
n=95967 -> next prime is 95971, previous prime is 95959, thus '9597195967' and '9596795959' and '959719596795959' are all three primes.
|
|
|
MATHEMATICA
|
ccatQ[n_]:=Module[{idn=IntegerDigits[n], pp=IntegerDigits[NextPrime[n, -1]], np= IntegerDigits[ NextPrime[n]]}, And@@PrimeQ[{FromDigits[ Join[np, idn]], FromDigits[Join[idn, pp]], FromDigits[Join[np, idn, pp]]}]]; Select[ Range[300000], ccatQ] (* From Harvey P. Dale, Sep 09 2011 *)
|
|
|
CROSSREFS
|
Cf. A034808-A034821.
Sequence in context: A088894 A015277 A135418 * A210091 A068260 A198207
Adjacent sequences: A034815 A034816 A034817 * A034819 A034820 A034821
|
|
|
KEYWORD
|
nonn,base
|
|
|
AUTHOR
|
Patrick De Geest, Oct 15 1998.
|
|
|
STATUS
|
approved
|
| |
|
|
