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A114889
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a(1)=1 and, for n>1, a(n) is the smallest integer greater than a(n-1) such that a(n)+a(i) is not a power of 3, for i=1,..., n-1.
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5
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1, 3, 4, 7, 9, 10, 11, 12, 13, 19, 21, 22, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 55, 57, 58, 61, 63, 64, 65, 66, 67, 73, 75, 76, 79, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| The differences of {a(n)}, together with a conjectured formula for them, is given in A114890.
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EXAMPLE
| Given that a(1)=1, a(2)=3 and a(3)=4, we find that a(4)>5 since 5+4=9 and a(4)>6 since 6+3=9. But none of 7+1, 7+3, or 7+4 is a power of 3, so a(4)=7.
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CROSSREFS
| Cf. A005652, A114890.
Sequence in context: A075773 A087276 A138225 * A174659 A010444 A010398
Adjacent sequences: A114886 A114887 A114888 * A114890 A114891 A114892
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KEYWORD
| nonn
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AUTHOR
| John W. Layman (layman(AT)math.vt.edu), Jan 04 2006
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