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A066540
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The first of two consecutive primes with equal digital sums.
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11
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523, 1069, 1259, 1759, 1913, 2503, 3803, 4159, 4373, 4423, 4463, 4603, 4703, 4733, 5059, 5209, 6229, 6529, 6619, 7159, 7433, 7459, 8191, 9109, 9749, 9949, 10691, 10753, 12619, 12763, 12923, 13763, 14033, 14107, 14303, 14369, 15859, 15973, 16529, 16673, 16903, 17239
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OFFSET
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1,1
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COMMENTS
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The difference between the two primes of the pair is a multiple of 18. - Antonio Roldán, Mar 13 2012
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LINKS
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EXAMPLE
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a(1) = 523 because both it and the next prime, 541, have a digital sum of 10.
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MATHEMATICA
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Prime[ Select[Range[2000], Apply[ Plus, IntegerDigits[ Prime[ # ]]] == Apply[ Plus, IntegerDigits[ Prime[ # + 1]]] & ]]
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PROG
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(PARI) SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) }
{ n=0; d=2; for (m=2, 10^10, s=SumD(prime(m)); if (s==d, write("b066540.txt", n++, " ", prime(m-1)); if (n==1000, return) ); d=s ) } \\ Harry J. Smith, Feb 22 2010
(Python)
from sympy import nextprime
from itertools import islice
def agen(): # generator of terms
p, hp, q, hq = 2, 2, 3, 3
while True:
if hp == hq: yield p
p, q = q, nextprime(q)
hp, hq = hq, sum(map(int, str(q)))
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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STATUS
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approved
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