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A257937
Primes p such that one digit appears exactly six times together with a single different digit.
1
1111151, 1111181, 1111211, 1111711, 1114111, 1117111, 1171111, 2999999, 3233333, 3331333, 3333133, 3333233, 3333313, 3333331, 3333373, 3333383, 3333433, 3337333, 3353333, 3433333, 3733333, 4999999, 7477777, 7577777, 7727777, 7772777, 7774777, 7777727, 7778777, 7877777, 9899999, 9929999, 9999299, 9999929, 9999991
OFFSET
1,1
COMMENTS
All the terms are congruent to 1 or 2 (mod 3).
In no term does the digit 0, 2, 4, 5, 6, or 8 appear six times.
LINKS
EXAMPLE
a(1) = 1111151 has exactly six 1's together with a single digit 5.
a(8) = 2999999 has exactly six 9's together with a single digit 2.
MAPLE
sort(select(isprime, [seq(seq(seq(d*1111111 + (a-d)*10^k, k=0..6), a={$1..9} minus {d}), d=1..9)])); # Robert Israel, Jul 13 2015
MATHEMATICA
kQ[n_]:= Module[{d=Select[DigitCount[n], # > 0 &]}, Length[d] == 2 && Min[d] == 1 && Max[d] == 6]; Select[Table[Prime[n], {n, 1000000}], kQ]
Select[Prime[Range[80000, 400000]], MemberQ[DigitCount[#], 6] &] (* Vincenzo Librandi, Jul 14 2015 *)
CROSSREFS
KEYWORD
nonn,base,fini,full
AUTHOR
K. D. Bajpai, Jul 13 2015
STATUS
approved