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Search: id:A092384
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| A092384 |
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Sum of digits of n if n even, else sum of digits of 2n. |
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+0
3
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| 0, 2, 2, 6, 4, 1, 6, 5, 8, 9, 1, 4, 3, 8, 5, 3, 7, 7, 9, 11, 2, 6, 4, 10, 6, 5, 8, 9, 10, 13, 3, 8, 5, 12, 7, 7, 9, 11, 11, 15, 4, 10, 6, 14, 8, 9, 10, 13, 12, 17, 5, 3, 7, 7, 9, 2, 11, 6, 13, 10, 6, 5, 8, 9, 10, 4, 12, 8, 14, 12, 7, 7, 9, 11, 11, 6, 13, 10, 15, 14, 8, 9, 10, 13, 12, 8, 14, 12, 16
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Inspired by Luhn algorithm for validating credit cards.
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FORMULA
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a(n) = sum of digits(if even n then n else 2n)
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EXAMPLE
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a(11) = 4 = 2 + 2 (2 and 2 are the digits in 22 = 2 * 11)
a(12) = 3 = 1 + 2 (1 and 2 are the digits in 12)
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MATHEMATICA
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f[n_] := Plus @@ IntegerDigits[ If[ EvenQ[n], n, 2n]]; Table[ f[n], {n, 0, 90}] (from Robert G. Wilson v Mar 24 2004)
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CROSSREFS
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Cf. A092383, A093150.
Sequence in context: A129889 A130712 A130728 this_sequence A061915 A138565 A137316
Adjacent sequences: A092381 A092382 A092383 this_sequence A092385 A092386 A092387
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KEYWORD
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easy,nonn,base
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AUTHOR
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Semaphore Corporation (help(AT)semaphorecorp.com), Mar 20 2004
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EXTENSIONS
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Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 21 2004
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