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Search: id:A115058
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| A115058 |
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Primes p that are also the largest prime factor of p(p^2-1)(3p+2)/24. |
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3
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| 2, 11, 31, 41, 47, 53, 61, 67, 71, 73, 101, 107, 109, 113, 131, 137, 151, 157, 179, 181, 191, 193, 211, 223, 229, 241, 251, 263, 271, 277, 281, 283, 307, 311, 331, 347, 359, 373, 379, 389, 401, 421, 431, 443, 449, 461, 463, 467, 487, 491, 509, 521, 541, 547
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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Number Theory, George E. Andrews 1971, Dover Publications New York, p 4.
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EXAMPLE
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p=11, p(p^2-1)(3p+2)/24 = 1925 = 5*5*7*11.
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MATHEMATICA
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a={}; Do[p=Prime[n]; If[ !PrimeQ[3*p+2], AppendTo[a, p]], {n, 8^2}]; a - Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 29 2008
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PROGRAM
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(PARI) g(n) = for(x=0, n, y=x*(x^2-1)*(3*x+2)/24; a=ifactord(y); z=a[length(a)]; if(x==z, print1(x", ") ) ifactord(n) = \The vector of the distinct integer factors of n (without \multiplicity). { local(f, j, k, flist); flist=[]; f=Vec(factor(n)); for(j=1, length(f[1]), flist = concat(flist, f[1][j]) ); return(flist) } )
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CROSSREFS
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Sequence in context: A023622 A119438 A094005 this_sequence A085041 A121346 A106847
Adjacent sequences: A115055 A115056 A115057 this_sequence A115059 A115060 A115061
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Feb 28 2006
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