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A180925
Natural numbers with palindromic number of divisors.
2
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70
OFFSET
1,2
COMMENTS
The first natural number not in this sequence is 48, which has 10 divisors. The complement of this sequence begins 48, 60, 72, 80, 84, 90, 96, 108, 112, 120, 126, 132, 140, 144, 150, 156, 160, 162, 168, 176, 180, 192, 198, 200, ... - Nathaniel Johnston, May 27 2011
LINKS
MAPLE
read(transforms): with(numtheory): A180925 := proc(n) option remember: local k, t: if(n=1)then return 1: fi: for k from procname(n-1)+1 do t:=tau(k): if(t=digrev(t))then return k: fi: od: end: seq(A180925(n), n=1..100); # Nathaniel Johnston, May 27 2011
CROSSREFS
Sequence in context: A268200 A296873 A044923 * A272302 A272443 A272437
KEYWORD
base,easy,nonn
AUTHOR
Giovanni Teofilatto, Sep 25 2010
STATUS
approved