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A177930 a(n) is the smallest prime divisor of (A177929(n)-1)*(A177929(n)+1). 6
3, 5, 3, 11, 3, 5, 3, 29, 3, 59, 3, 7, 5, 3, 7, 137, 3, 5, 3, 281, 3, 5, 3, 569, 3, 7, 5, 3, 1151, 3, 5, 3, 2309, 3, 31, 4649, 3, 17, 3, 7, 5, 3, 7, 5, 3, 9341, 3, 5, 3, 11, 3, 59, 3, 29, 3, 19, 7, 5, 3, 7, 19, 5, 3, 7, 109, 5, 3, 61, 7, 79, 5, 3, 13, 5, 3, 19139, 3, 101, 3, 7, 13, 11, 3, 71, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Records are in A177932, their positions in A177931.

LINKS

Table of n, a(n) for n=1..85.

FORMULA

a(n) = A020639( (A177929(n))^2 -1 ).

CROSSREFS

Cf. A001359, A177929, A174514, A174216, A174217

Sequence in context: A077862 A134061 A167221 * A242034 A205708 A309392

Adjacent sequences:  A177927 A177928 A177929 * A177931 A177932 A177933

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, May 15 2010

EXTENSIONS

A 7 replaced by 17 and sequence extended by R. J. Mathar, May 31 2010

STATUS

approved

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Last modified August 18 21:59 EDT 2019. Contains 326109 sequences. (Running on oeis4.)