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A120335 CRF(13): consecutive refactorable numbers (rf, rf-1 are refactorable) such that 13 is the smallest prime divisor of rf. 0
79600343456925208350554324952070658488321, 67727051825754224132985695308485992267126791150081, 17096333467784942360991864487916588941402614691799041 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence has prime factorization (13*197)^12, (13*1093)^12, (13*1733)^12, (13*17*139)^12, (13*7877)^12, (13*16069)^12.

LINKS

Table of n, a(n) for n=1..3.

FORMULA

a(n) = is the n-th number rf such that both rf and rf-1 are refactorable and 13 is the smallest prime divisor of rf.

EXAMPLE

a(1)=(13*197)^12 is the first number rf such that rf refactorable, 13 is the smallest prime of rf and rf-1 is refactorable.

CROSSREFS

Cf. A033950, A036898, A114617.

Sequence in context: A095474 A003944 A003937 * A095476 A292856 A292846

Adjacent sequences:  A120332 A120333 A120334 * A120336 A120337 A120338

KEYWORD

nonn,bref

AUTHOR

Walter Kehowski, Jun 22 2006

STATUS

approved

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Last modified July 15 16:09 EDT 2019. Contains 325049 sequences. (Running on oeis4.)