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Search: id:A129297
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A129297 Numbers m such that m^2-1 has no divisors d with 1<d<m-1. +0
4
0, 1, 2, 3, 4, 6, 12, 18, 30, 42, 60, 72, 102, 108, 138, 150, 180, 192, 198, 228, 240, 270, 282, 312, 348, 420, 432, 462, 522, 570, 600, 618, 642, 660, 810, 822, 828, 858, 882, 1020, 1032, 1050, 1062, 1092, 1152, 1230, 1278, 1290, 1302, 1320, 1428, 1452, 1482, 1488 (list; graph; listen)
OFFSET

1,3

COMMENT

A129296(a(n)) = #{1, a(n)-1} = 2;

a(n) = A014574(n-2) for n>1.

EXAMPLE

{1,41,43,1763} is the set of divisors of 42^2-1, therefore 42 is a term, A129296(42) = #{1,41} = 2.

CROSSREFS

Cf. A129293, A129295.

Sequence in context: A037393 A048330 A118651 this_sequence A018343 A102462 A018369

Adjacent sequences: A129294 A129295 A129296 this_sequence A129298 A129299 A129300

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 09 2007

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Last modified November 23 10:40 EST 2009. Contains 167421 sequences.


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