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A141469
Nonprimes of the form c(c(i)-3)-3, where A002808(i)=c(i)=i-th composite.
0
1, 9, 18, 22, 24, 25, 27, 30, 32, 33, 35, 42, 45, 46, 48, 49, 51, 55, 57, 62, 63, 65, 66, 69, 72, 74, 77, 81, 82, 84, 87, 88, 91, 93, 95, 96, 99, 102, 105, 108, 111, 112, 115, 116, 117, 118, 119, 120, 121, 123, 125, 126, 129, 132, 133, 140, 141, 143, 144, 145, 147, 150
OFFSET
1,2
EXAMPLE
If i=1, then c(c(1)-3)-3=c(4-3)-3=4-3=1=a(1).
If i=4, then c(c(4)-3)-3=c(9-3)-3=12-3=9=a(2).
If i=8, then c(c(8)-3)-3=c(15-3)-3=21-3=18=a(3).
If i=10, then c(c(10)-3)-3=c(18-3)-3=25-3=22=a(4).
If i=11, then c(c(11)-3)-3=c(20-3)-3=27-3=24=a(5),
etc.
CROSSREFS
Cf. A002808.
Sequence in context: A306382 A373351 A222623 * A046412 A171081 A232056
KEYWORD
nonn
AUTHOR
EXTENSIONS
58 and 73 removed by R. J. Mathar, Sep 05 2008
STATUS
approved