|
|
A158217
|
|
Primes whose digit sum is a single-digit prime.
|
|
2
|
|
|
2, 3, 5, 7, 11, 23, 41, 43, 61, 101, 113, 131, 151, 223, 241, 311, 313, 331, 401, 421, 601, 1013, 1031, 1033, 1051, 1103, 1123, 1213, 1231, 1301, 1303, 1321, 2003, 2111, 2113, 2131, 2203, 2221, 2311, 3011, 3121, 3301, 4001, 4003, 4021, 4111, 4201, 5011, 5101
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
EXAMPLE
|
The digit sum of the prime 421 is 7, which is a single-digit prime.
|
|
MATHEMATICA
|
okQ[n_]:=Module[{ans=Plus@@IntegerDigits[n]}, ans<10&&PrimeQ[ans]]; Select[Prime[Range[1000]], okQ] (* Harvey P. Dale, May 27 2009 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|