|
|
A285096
|
|
Primes with integer arithmetic mean of digits = 2 in base 10.
|
|
6
|
|
|
2, 13, 31, 1061, 1151, 1223, 1511, 1601, 2141, 2213, 2411, 3023, 3041, 3203, 3221, 4013, 4211, 5003, 5021, 6011, 6101, 7001, 10009, 10243, 10333, 10513, 10531, 10711, 11071, 11161, 11251, 11503, 11701, 12007, 12043, 12241, 12421, 12511, 12601, 13033, 13411
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
MAPLE
|
S:= proc(d, k, flag) option remember;
if d = 1 then
if k >= 0 and k <= 9 then return [k]
else return []
fi
fi;
[seq(op(map(`+`, procname(d-1, k-i, 0), i*10^(d-1))), i=flag..min(k, 9))]
end proc:
seq(op(select(isprime, S(d, 2*d, 1))), d=1..5); # Robert Israel, Apr 23 2017
|
|
MATHEMATICA
|
Select[Prime[Range[1600]], Mean[IntegerDigits[#]]==2&] (* Harvey P. Dale, Aug 07 2021 *)
|
|
PROG
|
(Magma) [n: n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0 and &+Intseq(n) / #Intseq(n) eq 2]
|
|
CROSSREFS
|
Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), this sequence (k = 2), A285225 (k = 4), A285226 (k = 5), A285227 (k = 7), A285228 (k = 8).
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|