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%I #6 Jul 25 2015 01:02:10
%S 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,
%T 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,
%U 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
%N Sum of digits of n if n odd, else sum of digits of 2n.
%C Inspired by Luhn algorithm for validating credit cards.
%F a(n) = sum of digits(if n odd then n else 2n).
%e a(11) = 2 = 1 + 1 (1 and 1 are the digits in 11).
%e a(12) = 6 = 2 + 4 (2 and 4 are the digits in 24 = 2 * 12).
%t f[n_] := Plus @@ IntegerDigits[ If[ OddQ[n], n, 2n]]; Table[ f[n], {n, 0, 90}] (* _Robert G. Wilson v_, Mar 24 2004 *)
%Y Cf. A092384, A093150.
%K easy,nonn,base
%O 0,3
%A Semaphore Corporation (help(AT)semaphorecorp.com), Mar 20 2004
%E Corrected and extended by _Ray Chandler_, Mar 21 2004
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