A285228 Primes with integer arithmetic mean of digits = 8 in base 10.

79, 97, 6899, 8699, 8969, 9689, 9887, 49999, 68899, 69997, 77899, 78889, 78979, 79699, 79987, 85999, 88789, 88897, 88969, 89599, 89689, 89779, 89797, 89959, 89977, 94999, 95989, 96799, 96979, 96997, 97789, 97879, 97987, 98689, 98779, 98869, 98887, 99679, 99787

Offset

1,1

Links

Jaroslav Krizek, Table of n, a(n) for n = 1..1000

Mathematica

Select[Prime@ Range@ PrimePi[10^5], Mean@ IntegerDigits@ # == 8 &] (* Michael De Vlieger, Apr 22 2017 *)

Prog

(Magma) [n: n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0 and &+Intseq(n) / #Intseq(n) eq 8];
(Python)
from itertools import count, islice
from collections import Counter
from sympy.utilities.iterables import partitions, multiset_permutations
def A285228_gen(): # generator of terms
    for l in count(2):
        for i in range(1, 10):
            yield from sorted(q for q in (int(str(i)+''.join(map(str, j))) for s, p in partitions((l<<3)-i, m=l-1, k=9, size=True) for j in multiset_permutations([0]*(l-1-s)+list(Counter(p).elements()))) if isprime(q))
A285228_list = list(islice(A285228_gen(), 30)) # Chai Wah Wu, Nov 28 2023

Crossrefs

Primes from A061425. Subsequence of A069709.

Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), A285096 (k = 2), A285225 (k = 4), A285226 (k = 5), A285227 (k = 7), this sequence (k = 8).

Sequence in context: A044039 A065211 A106757 * A087537 A117840 A296012

Adjacent sequences: A285225 A285226 A285227 * A285229 A285230 A285231

Keyword

nonn,base

Author

Jaroslav Krizek, Apr 19 2017

Status

approved