|
Search: id:A161404
|
|
|
| A161404 |
|
Numbers n such that the count of primes among the permutations of the digits of n is greater than 7. |
|
+0
1
|
|
| 1013, 1031, 1039, 1049, 1079, 1093, 1094, 1097, 1103, 1123, 1130, 1132, 1139, 1193, 1213, 1231, 1237, 1273, 1279, 1297, 1301, 1309, 1310, 1312, 1319, 1321, 1327, 1349, 1367, 1372, 1376, 1390, 1391, 1394, 1409, 1439, 1457, 1475, 1478, 1487, 1490, 1493
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Leading zeros in the permutations are ignored.
|
|
LINKS
|
C. Hilliard, Comments and PARI program.
Wikipedia, Permutation
|
|
EXAMPLE
|
1013 has eight permutations of its digits 1, 0, 1, 3 that form a prime, namely 113, 131, 311, 1013, 1031, 1103, 1301, 3011. So the count of primes for 1013 is greater than 7 and 1013 is in the sequence.
|
|
PROGRAM
|
(PARI) Cf. C. Hilliard link.
(MAGMA) [ n: n in [1..1500] | #[ s: s in Seqset([ Seqint([m(p[i]):i in [1..#x] ], 10): p in Permutations(Seqset(x)) ]) | IsPrime(s) ] gt 7 where m is map< x->y | [<x[i], y[i]>:i in [1..#x] ] > where x is [1..#y] where y is Intseq(n, 10) ]; [From Klaus Brockhaus, Jun 14 2009]
|
|
CROSSREFS
|
Sequence in context: A165295 A069489 A157008 this_sequence A126239 A120214 A096928
Adjacent sequences: A161401 A161402 A161403 this_sequence A161405 A161406 A161407
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
Cino Hilliard (hillcino368(AT)hotmail.com), Jun 09 2009
|
|
EXTENSIONS
|
Edited by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 14 2009
|
|
|
Search completed in 0.002 seconds
|
