

A053392


a(n) is the concatenation of the sums of every pair of consecutive digits of n (with a(n) = 0 for 0 <= n <= 9).


5



0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 210
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,12


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
Erich Friedman, Problem of the Month (February 2000).


EXAMPLE

For n=10 we have 10 > 1+0 = 1, hence a(10)=1;
987 > 9+8.8+7 > 17.15 > 1715, so a(987)=1715.


MATHEMATICA

a[n_] := Total /@ Transpose[{Most[id = IntegerDigits[n]], Rest[id]}] // IntegerDigits // Flatten // FromDigits; Table[a[n], {n, 0, 119}] (* JeanFrançois Alcover, Apr 05 2013 *)


PROG

(Haskell)
a053392 :: Integer > Integer
a053392 n = if ys == "" then 0 else read ys where
ys = foldl (++) "" $ map show $ zipWith (+) (tail ds) ds
ds = (map (read . return) . show) n
 Reinhard Zumkeller, Nov 26 2013


CROSSREFS

Cf. A053393, A060630, A1003117, A194429.
Sequence in context: A117230 A093882 A138953 * A114925 A043270 A089898
Adjacent sequences: A053389 A053390 A053391 * A053393 A053394 A053395


KEYWORD

nonn,easy,nice,base,look


AUTHOR

N. J. A. Sloane, Jan 07 2000


STATUS

approved



