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Re: [PrimeNumbers] Extension of Cunningham chains

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  • Jack Brennen
    ... Add to that a 4-divisor Cunningham chain (of the first kind) of length 18: 899643225*2^8+1 == 173 * 1331263963 899643225*2^9+1 == 2347 * 196257917
    Message 1 of 6 , Nov 13, 2004
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      I previously wrote:
      > So far, I've found a "4-divisor Cunningham chain" (of the second kind)
      > of length 18...

      Add to that a "4-divisor Cunningham chain" (of the first kind) of length 18:

      899643225*2^8+1 == 173 * 1331263963
      899643225*2^9+1 == 2347 * 196257917
      899643225*2^10+1 == 53 * 17381786083
      899643225*2^11+1 == 397 * 4640980667
      899643225*2^12+1 == 821 * 4488354019
      899643225*2^13+1 == 2351 * 3134784049
      899643225*2^14+1 == 1531 * 9627534029
      899643225*2^15+1 == 19 * 1551553115621
      899643225*2^16+1 == 71 * 830408709769
      899643225*2^17+1 == 11 * 10719821526109
      899643225*2^18+1 == 193 * 1221948567743
      899643225*2^19+1 == 101 * 4670021258899
      899643225*2^20+1 == 532663 * 1770996473
      899643225*2^21+1 == 499 * 3780939055301
      899643225*2^22+1 == 9008023 * 418890713
      899643225*2^23+1 == 19427 * 388467306037
      899643225*2^24+1 == 122953 * 122758360583
      899643225*2^25+1 == 5205467 * 5799098797


      So I've got two examples of length 18, a "4DCC1K" and a "4DCC2K". :)


      The challenge is this: find a chain of length 19, any number
      of divisors you wish. :)
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