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A240886
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Primes p equal to the sum in base-3 of the digits of all primes < p.
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6
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23, 31, 47, 59, 695689, 698471, 883517, 992609, 992737, 993037, 1314239, 1324361, 1324571, 1326511, 1327289, 1766291, 3174029
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OFFSET
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1,1
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COMMENTS
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Conjecture: this sequence is finite and all terms are shown. - Robert G. Wilson v, Jul 27 2014
The sum of the digits in base three of all primes < 10^10 is 9694409092. - Robert G. Wilson v, Jul 27 2014
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LINKS
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FORMULA
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prime(n) such that, using base 3, prime(n) = sum_{1..n-1} A239619(i).
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EXAMPLE
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For example, 23 = digit-sum(primes < 23, base=3) = sum(2) + sum(1,0) + sum(1,2) + sum(2,1) + sum(1,0,2) + sum(1,1,1) + sum(1,2,2) + sum(2,0,1).
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MATHEMATICA
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p = 2; s = 0; lst = {}; While[p < 3200000, If[s == p, AppendTo[lst, p]; Print[p]]; s = s + Total@ IntegerDigits[p, 3]; p = NextPrime[p]] (* Robert G. Wilson v, Jul 27 2014 *)
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PROG
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(PARI) sdt(n) = my(d = digits(n, 3)); sum(i=1, #d, d[i]);
lista(nn) = {sp = 0; forprime(p=1, nn, if (p == sp, print1(p, ", ")); sp += sdt(p); ); } \\ Michel Marcus, May 02 2014
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CROSSREFS
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Cf. A239619 (Base 3 sum of digits of prime(n)).
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KEYWORD
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nonn,base,more
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AUTHOR
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STATUS
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approved
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