

A092383


Sum of digits of n if n odd, else sum of digits of 2n.


2



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
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OFFSET

0,3


COMMENTS

Inspired by Luhn algorithm for validating credit cards.


LINKS

Table of n, a(n) for n=0..86.


FORMULA

a(n) = sum of digits(if n odd then n else 2n).


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).


MATHEMATICA

f[n_] := Plus @@ IntegerDigits[ If[ OddQ[n], n, 2n]]; Table[ f[n], {n, 0, 90}] (* Robert G. Wilson v, Mar 24 2004 *)


CROSSREFS

Cf. A092384, A093150.
Sequence in context: A021962 A097672 A103339 * A227242 A156028 A021232
Adjacent sequences: A092380 A092381 A092382 * A092384 A092385 A092386


KEYWORD

easy,nonn,base


AUTHOR

Semaphore Corporation (help(AT)semaphorecorp.com), Mar 20 2004


EXTENSIONS

Corrected and extended by Ray Chandler, Mar 21 2004


STATUS

approved



