|
|
A048528
|
|
Primes expressible in two ways as the sum of an integer and its digit sum.
|
|
2
|
|
|
101, 103, 107, 109, 113, 307, 311, 313, 317, 509, 521, 709, 719, 911, 919, 1009, 1013, 1213, 1217, 1409, 1607, 1609, 1613, 1619, 1621, 1811, 1823, 2017, 2027, 2111, 2113, 2309, 2311, 2521, 2711, 2713, 2719, 2917, 2927, 3011, 3209, 3217, 3221, 3407, 3413, 3613, 3617, 3623
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
EXAMPLE
|
313 = 296 + (2+9+6) and 313 = 305 + (3+0+5).
|
|
MATHEMATICA
|
Transpose[Select[Tally[Select[#+Total[IntegerDigits[#]]&/@ Range[ 5000], PrimeQ]], #[[2]]==2&]][[1]] (* Harvey P. Dale, May 09 2013 *)
|
|
PROG
|
(Python)
from collections import Counter
from sympy import isprime
def a_list(upto):
return [i for i, j in Counter([i+sum(map(int, str(i))) for i in range(upto)]).items() if j>1 and isprime(i)]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base,nice
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|