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A167611
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Nonprimes that are the sum of two consecutive nonprimes.
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3
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1, 10, 14, 22, 26, 34, 38, 46, 49, 51, 55, 58, 62, 65, 69, 74, 77, 82, 86, 91, 94, 99, 106, 111, 115, 118, 122, 125, 129, 134, 142, 146, 153, 155, 158, 161, 166, 169, 171, 175, 178, 183, 185, 187, 189, 194, 202, 206, 209, 214, 218, 221, 226, 231, 235, 237, 243
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OFFSET
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1,2
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COMMENTS
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One and composite numbers that are the sum of two consecutive composite numbers.
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LINKS
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EXAMPLE
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a(1) = 1st nonprime + 2nd nonprime = 0 + 1 = 1, which is nonprime;
a(2) = 3rd nonprime + 4th nonprime = 4 + 6 = 10, which is nonprime.
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PROG
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(Magma) m:=150; NonPrime:=[i: i in [0..m] | not IsPrime(i)]; [q: n in [1..#NonPrime-1] | not IsPrime(q) where q is NonPrime[n]+NonPrime[n+1]]; // Bruno Berselli, Apr 05 2014
(Python)
from sympy import isprime, composite
print([1] + [totest for k in range(1, 91) if not isprime(totest := composite(k) + composite(k+1))]) # Karl-Heinz Hofmann, Jan 25 2024
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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