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A369251
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Numbers that have at least one representation as a sum (p*q + p*r + q*r) with three odd primes p <= q <= r.
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8
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27, 39, 51, 55, 71, 75, 87, 91, 95, 103, 111, 119, 123, 131, 135, 147, 151, 155, 167, 183, 187, 191, 195, 199, 203, 211, 215, 231, 239, 247, 251, 255, 263, 267, 271, 275, 287, 291, 299, 311, 315, 327, 331, 335, 343, 351, 355, 359, 363, 371, 375, 383, 391, 395, 407, 411, 419, 423, 431, 435, 439, 447, 451, 455, 459
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OFFSET
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1,1
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COMMENTS
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By necessity all terms are of the form 4m+3 (in A004767).
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LINKS
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FORMULA
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PROG
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(PARI) isA369251(n) = if(3!=(n%4), 0, my(v = [3, 3], ip = #v, r); while(1, r = (n-(v[1]*v[2])) / (v[1]+v[2]); if(r < v[2], ip--, ip = #v; if(1==denominator(r) && isprime(r), return(1))); if(!ip, return(0)); v[ip] = nextprime(1+v[ip]); for(i=1+ip, #v, v[i]=v[i-1])));
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CROSSREFS
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Sequence A369252 sorted into ascending order, with duplicates removed.
Cf. A369250 (primes in this sequence).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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