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 A161751 Digital root of Abelian numbers (A051532). 0
 1, 2, 3, 4, 5, 7, 9, 2, 4, 6, 8, 1, 5, 7, 2, 4, 6, 8, 1, 5, 7, 9, 2, 4, 6, 8, 5, 7, 2, 4, 6, 8, 1, 5, 7, 2, 4, 6, 8, 1, 5, 7, 9, 2, 4, 8, 1, 5, 7, 2, 4, 6, 1, 5, 7, 2, 4, 6, 8, 1, 5, 7, 9, 4, 6, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS It is interesting to observe that it is difficult to find 3 as the digital root. This is because if a member of A051532 is congruent to 3 mod 9 all other prime power divisors of the number must be 2 mod 3.  The first few indexes n with a(n) = 3 are 3, 99, 131, 164, 211, 261, 293, 327, 351, 424, 450, 482, 491, .... [From Charles R Greathouse IV, Feb 13 2011] LINKS EXAMPLE 161 is an Abelian number whose digital root is 8. CROSSREFS Cf. A051532 Sequence in context: A099088 A029447 A212317 * A245820 A105362 A115928 Adjacent sequences:  A161748 A161749 A161750 * A161752 A161753 A161754 KEYWORD nonn,base AUTHOR Parthasarathy Nambi, Jun 17 2009 STATUS approved

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Last modified January 18 16:27 EST 2020. Contains 331011 sequences. (Running on oeis4.)