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A087997 a(n) is the least number with n palindromic divisors. 1
1, 2, 4, 6, 12, 24, 72, 66, 484, 132, 616, 264, 2112, 792, 1848, 2772, 7326, 8712, 5544, 13332, 14652, 24024, 36036, 26664, 87912, 102564, 72072, 79992, 186648, 205128, 360360, 279972, 264264, 666666, 1213212, 879912, 559944, 888888, 792792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..150

FORMULA

a(n)=Min{x; A087990[x]=n}

EXAMPLE

n=24: a(24)=26664 has 32 divisors of which 24 are palindromic numbers:

{1,2,3,4,6,8,11,22,33,44,66,88,101,202,303,404,

606,808,1111,2222,3333,4444,6666,8888}.

Some solutions are palindromic (like 2112), some are not (like 132).

MATHEMATICA

t = Table[Count[Divisors[k], _?(Reverse[x = IntegerDigits[#]] == x &)], {k, 2, 15*10^5, 2}]; Join[{1}, Table[i = 1; While[t[[i]] != k, i++]; 2 i, {k, 2, 39}]] (* Jayanta Basu, Aug 12 2013 *)

CROSSREFS

Cf. A087990.

Sequence in context: A036484 A212654 A093036 * A177905 A118405 A095912

Adjacent sequences:  A087994 A087995 A087996 * A087998 A087999 A088000

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Oct 13 2003

EXTENSIONS

More terms from Ray Chandler, Oct 17 2003

STATUS

approved

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Last modified November 22 01:14 EST 2019. Contains 329383 sequences. (Running on oeis4.)