21^119+1

  Henrik Olsen announces the complete factorization of the number
N=(21^119+1)/(21^17+1) from Richard Brent's Factor Tables by the
Special Number Field Sieve (SNFS).  It was previously known that

        N = 239 * 78541 * 81867661 * c120

where c120 is a 120 digit composite number given by

 c120 = 4783671547769691167869159778845602816932\
        3089880924091128273891832786876404450240\
        5549009310094838359239954378856224771339

The two polynomials used were

        X^6 - X^5 + X^4 - X^3 + X^2 - X + 1 and
        X - 21^17

with common root 21^17 (mod N).

  The region sieved was b < 381200 and |a| < 9437184.
A factorbase size of 150000 and large prime bound of
25M was used for both polynomials.

  A total of 2430835 relations was collected forming a
620K X 625K matrix.
The linear algebra phase was done by Conrad Curry.

  On Jan 4, 2000 it was found that c120 = p60 * p61 where

p60 = 456547149396215146316989552005017911648766803061935886988961

p61 = 1047793542046228932239094186657681797677507847051755213152299

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