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Search: id:A088579
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| A088579 |
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Primes of the form n*x^n + (n-1)*x^(n-1) + . . . + x + 1 for x=2. |
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+0
1
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| 3, 11, 643, 425987, 1909526242005090307, 23022895558580442706439279569724601504895911302154162237586282577237116573795771\ 448387257510093253287303723617020373843853928820634751104133890051
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sum of reciprocals = 0.4257999816852453227652727311.. If x=1 this becomes A055469.
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EXAMPLE
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2*2^2 + 1*2 + 1 = 11
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MATHEMATICA
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Select[Table[1+Sum[k 2^k, {k, n}], {n, 1000}], PrimeQ] - T. D. Noe (noe(AT)sspectra.com), Nov 15 2006
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PROGRAM
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(PARI) trajpolyp(n1, k) = { s=0; for(x1=0, n1, y1 = polypn2(k, x1); if(isprime(y1), print1(y1", "); s+=1.0/y1; ) ); print(); print(s) } polypn2(n, p) = { x=n; y=1; for(m=1, p, y=y+m*x^m; ); return(y) }
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CROSSREFS
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Sequence in context: A112357 A097423 A111130 this_sequence A145988 A124984 A034797
Adjacent sequences: A088576 A088577 A088578 this_sequence A088580 A088581 A088582
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Nov 20 2003
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EXTENSIONS
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Corrected by T. D. Noe and Don Reble, Nov 15, 2006
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