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A092383
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Sum of digits of n if n odd, else sum of digits of 2n.
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2
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0, 1, 4, 3, 8, 5, 3, 7, 7, 9, 2, 2, 6, 4, 10, 6, 5, 8, 9, 10, 4, 3, 8, 5, 12, 7, 7, 9, 11, 11, 6, 4, 10, 6, 14, 8, 9, 10, 13, 12, 8, 5, 12, 7, 16, 9, 11, 11, 15, 13, 1, 6, 5, 8, 9, 10, 4, 12, 8, 14, 3, 7, 7, 9, 11, 11, 6, 13, 10, 15, 5, 8, 9, 10, 13, 12, 8, 14, 12, 16, 7, 9, 11, 11, 15, 13, 10
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Inspired by Luhn algorithm for validating credit cards.
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FORMULA
| a(n) = sum of digits(if n odd then n else 2n)
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EXAMPLE
| a(11) = 2 = 1 + 1 (1 and 1 are the digits in 11)
a(12) = 6 = 2 + 4 (2 and 4 are the digits in 24 = 2 * 12)
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MATHEMATICA
| f[n_] := Plus @@ IntegerDigits[ If[ OddQ[n], n, 2n]]; Table[ f[n], {n, 0, 90}] (from Robert G. Wilson v Mar 24 2004)
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CROSSREFS
| Cf. A092384, A093150.
Sequence in context: A021962 A097672 A103339 * A156028 A021232 A022998
Adjacent sequences: A092380 A092381 A092382 * A092384 A092385 A092386
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KEYWORD
| easy,nonn,base
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AUTHOR
| Semaphore Corporation (help(AT)semaphorecorp.com), Mar 20 2004
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EXTENSIONS
| Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 21 2004
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