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A036455
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Applying A000005 thrice to a[ n ] we get 2.
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6
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6, 8, 10, 14, 15, 21, 22, 26, 27, 33, 34, 35, 36, 38, 39, 46, 51, 55, 57, 58, 62, 65, 69, 74, 77, 82, 85, 86, 87, 91, 93, 94, 95, 100, 106, 111, 115, 118, 119, 120, 122, 123, 125, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 168, 177, 178, 183
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Compare with sequence A007422 and A030513-the resemblance is rather strong. Still this sequence is different. E.g. 36,100,120,168 are not here present.
The definition implies that numbers which reach 2 already after two applications of A000005 (see A009087) are not included. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 20 2008]
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FORMULA
| d[ d[ d[ a[ n ] ] ] ] = 2 for all n
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EXAMPLE
| a[ 15 ]=39 and d[ 39 ]=4, d[ d[ 39 ] ]=d[ 4 ]=3 and d[ d[ d[ 39 ] ] ]=2. After 3 iteration the equilibrium is reached.
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CROSSREFS
| A007422, A030513, A036450, A036452, A036454-A036458.
Sequence in context: A130763 A120497 A036436 * A007422 A030513 A161918
Adjacent sequences: A036452 A036453 A036454 * A036456 A036457 A036458
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu)
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