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A210767
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Numbers whose digit sum as well as sum of the 4th powers of the digits is a prime.
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3
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11, 12, 14, 16, 21, 23, 25, 29, 32, 34, 38, 41, 43, 47, 52, 58, 61, 67, 74, 76, 83, 85, 89, 92, 98, 101, 102, 104, 106, 110, 111, 113, 119, 120, 131, 133, 140, 146, 160, 164, 166, 179, 191, 197, 201, 203, 205, 209, 210, 223, 230, 232, 250, 269, 290, 296, 302
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OFFSET
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1,1
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COMMENTS
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This is to the exponent 4 as A182404 is to the exponent 2.
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LINKS
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FORMULA
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EXAMPLE
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21 is in the sequence because sum of digits 2+1= 3 is prime, and sum of the 4th powers of the digits 2^4+1^4=17 is a prime.
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MATHEMATICA
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Select[Range[350], AllTrue[{Total[IntegerDigits[#]], Total[ IntegerDigits[ #]^4]}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Apr 01 2019 *)
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PROG
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(PARI) dspow(n, b, k)=my(s); while(n, s+=(n%b)^k; n\=b); s
select(n->isprime(sumdigits(n))&&isprime(dspow(n, 10, 4)), vector(10^3, i, i)) \\ Charles R Greathouse IV, May 11 2012
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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