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A088579 Primes of the form n*x^n + (n-1)*x^(n-1) + . . . + x + 1 for x=2. 0
3, 11, 643, 425987, 1909526242005090307, 23022895558580442706439279569724601504895911302154162237586282577237116573795771448387257510093253287303723617020373843853928820634751104133890051 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sum of reciprocals = 0.4257999816852453227652727311.. If x=1 this becomes A055469.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

2*2^2 + 1*2 + 1 = 11

MATHEMATICA

Select[Table[1+Sum[k 2^k, {k, n}], {n, 1000}], PrimeQ] - T. D. Noe, Nov 15 2006

PROG

(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) }

CROSSREFS

Sequence in context: A111130 A337415 A264725 * A006938 A124984 A287432

Adjacent sequences:  A088576 A088577 A088578 * A088580 A088581 A088582

KEYWORD

nonn

AUTHOR

Cino Hilliard, Nov 20 2003

EXTENSIONS

Corrected by T. D. Noe and Don Reble, Nov 15 2006

STATUS

approved

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Last modified September 30 05:00 EDT 2020. Contains 337434 sequences. (Running on oeis4.)