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 A343275 a(n) = |2*n - 10^length(n)|. 1
 8, 6, 4, 2, 0, 2, 4, 6, 8, 80, 78, 76, 74, 72, 70, 68, 66, 64, 62, 60, 58, 56, 54, 52, 50, 48, 46, 44, 42, 40, 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The plot looks like multiple V shapes. A new V shape occurs for each interval n = 10^k .. 10^(k+1)-1, with the bottom of the V at a(5*10^k) = 0. All terms are even. LINKS Rémy Sigrist, Table of n, a(n) for n = 1..9999 Erhan Tezcan, Github Repo includes plots and the code. FORMULA a(n) = abs(2*n - 10^A055642(n)). a(10*n) = 10*a(n). EXAMPLE n=10 has length 2, so a(10) = |20-100| = 80. PROG (Python) def a(n : int) -> int: return abs((n << 1) - (10 ** len(str(n)))) (PARI) a(n) = abs(2*n-10^max(1, #digits(n))) \\ Rémy Sigrist, May 30 2021 CROSSREFS Cf. A055642. Sequence in context: A263181 A298978 A199151 * A177154 A059631 A333198 Adjacent sequences: A343272 A343273 A343274 * A343276 A343277 A343278 KEYWORD nonn,base AUTHOR Erhan Tezcan, Apr 10 2021 STATUS approved

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Last modified December 9 00:20 EST 2022. Contains 358698 sequences. (Running on oeis4.)