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Search: id:A072201
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| A072201 |
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a(n) = 4*a(n-1)+1, a(1) = 15. |
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+0
1
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| 15, 61, 245, 981, 3925, 15701, 62805, 251221, 1004885, 4019541, 16078165, 64312661, 257250645, 1029002581, 4116010325, 16464041301, 65856165205, 263424660821, 1053698643285, 4214794573141, 16859178292565
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OFFSET
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1,1
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COMMENT
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These are the integers N which on application of the Collatz function yield the number 23. The Collatz function: if N is an odd number then (3N+1)/2^r yields a positive odd integer for some value of r (which in this case is 11).
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FORMULA
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a(n) = (23*4^n-2)/6.
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CROSSREFS
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Adjacent sequences: A072198 A072199 A072200 this_sequence A072202 A072203 A072204
Sequence in context: A001756 A022288 A041432 this_sequence A067572 A066584 A065915
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KEYWORD
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nonn
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AUTHOR
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N. Rathankar (rathankar(AT)yahoo.com), Jul 03 2002
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EXTENSIONS
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Edited and extended by Henry Bottomley (se16(AT)btinternet.com), Aug 05 2002
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