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A087999
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a(n) is the LCM of palindromic divisors of n.
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7
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 14, 15, 8, 1, 18, 1, 20, 21, 22, 1, 24, 5, 2, 9, 28, 1, 30, 1, 8, 33, 2, 35, 36, 1, 2, 3, 40, 1, 42, 1, 44, 45, 2, 1, 24, 7, 10, 3, 4, 1, 18, 55, 56, 3, 2, 1, 60, 1, 2, 63, 8, 5, 66, 1, 4, 3, 70, 1, 72, 1, 2, 15, 4, 77, 6, 1, 40, 9, 2, 1, 84, 5, 2, 3, 88
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OFFSET
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1,2
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COMMENTS
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Sequence is not multiplicative. For example, a(141) = 141 != a(3)*a(47) = 3 * 1. - Franklin T. Adams-Watters, Oct 27 2006
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LINKS
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Indranil Ghosh, Table of n, a(n) for n = 1..50000
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FORMULA
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a(n)=1 for non-palindromic primes like 13.
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EXAMPLE
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n=252: a(252)=252=n,since palindromic divisors = {1,2,3,4,6,7,9,252};
n=255: a(255)=15<n, palind.div ={1,3,5}.
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MATHEMATICA
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Table[LCM @@ Select[Divisors[k], Reverse[x = IntegerDigits[#]] == x &], {k, 88}] (* Jayanta Basu, Aug 12 2013 *)
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PROG
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(PARI) ispal(x) = my(d=digits(x)); d == Vecrev(d);
a(n) = lcm(select(x->ispal(x), divisors(n))); \\ Michel Marcus, Mar 27 2020
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CROSSREFS
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Cf. A087990.
Sequence in context: A034326 A053833 A167973 * A106614 A297242 A043272
Adjacent sequences: A087996 A087997 A087998 * A088000 A088001 A088002
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KEYWORD
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base,nonn
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AUTHOR
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Labos Elemer, Oct 14 2003
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STATUS
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approved
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