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A061470
First (leftmost) digit - second digit + third digit - fourth digit .... = 1.
28
1, 10, 21, 32, 43, 54, 65, 76, 87, 98, 100, 111, 122, 133, 144, 155, 166, 177, 188, 199, 210, 221, 232, 243, 254, 265, 276, 287, 298, 320, 331, 342, 353, 364, 375, 386, 397, 430, 441, 452, 463, 474, 485, 496, 540, 551, 562, 573, 584, 595, 650, 661, 672, 683
OFFSET
1,2
LINKS
FORMULA
A225693(a(n)) = 1. - Reinhard Zumkeller, Aug 08 2014
EXAMPLE
221 is in the sequence since 2-2+1 = 1.
MATHEMATICA
d[n_]:=IntegerDigits[n]; a[n_]:=Differences[Reverse[Total/@{Take[d[n], {1, -1, 2}], Take[d[n], {2, -1, 2}]}]]; Select[Range[690], a[#]=={1} &] (* Jayanta Basu, May 18 2013 *)
Select[Range[1000], Total[Times@@@Partition[Riffle[IntegerDigits[#], {1, -1}, {2, -1, 2}], 2]]==1&] (* Harvey P. Dale, May 24 2021 *)
PROG
(Haskell)
a061470 n = a061470_list !! (n-1)
a061470_list = filter ((== 1) . a225693) [0..]
-- Reinhard Zumkeller, Aug 08 2014
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, May 05 2001
EXTENSIONS
More terms from Robert G. Wilson v, May 10 2001 and from Larry Reeves (larryr(AT)acm.org), May 14 2001
STATUS
approved