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 A038444 Sums of 2 distinct powers of 10. 17
 11, 101, 110, 1001, 1010, 1100, 10001, 10010, 10100, 11000, 100001, 100010, 100100, 101000, 110000, 1000001, 1000010, 1000100, 1001000, 1010000, 1100000, 10000001, 10000010, 10000100, 10001000, 10010000, 10100000, 11000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA G.f.: (10*x - 55*x^2 + Sum_{d>=1} (4*10^d+5)*x^((d^2-d)/2+1) - Sum_{d>=1} (445*10^(d-1)+5)*x^((d^2-d)/2+2))/(5*(1-x)*(1-10*x)). - Robert Israel, Oct 14 2016 MAPLE seq(seq(10^d + 10^j, j=0..d-1), d=1..10); # Robert Israel, Oct 14 2016 MATHEMATICA Sort[Total/@Subsets[10^Range[0, 7], {2}]] (* Harvey P. Dale, Apr 20 2012 *) PROG (Haskell) a038444 n = a038444_list !! (n-1) a038444_list = 11 : f [11] 90 where    f xs@(x:_) z = ys ++ f ys (10 * z) where                   ys = (x + z) : map (* 10) xs -- Reinhard Zumkeller, Jan 28 2015 CROSSREFS Subsequence of A052216. Sequence in context: A043494 A277959 A278937 * A115824 A208259 A043036 Adjacent sequences:  A038441 A038442 A038443 * A038445 A038446 A038447 KEYWORD nonn,easy AUTHOR EXTENSIONS Offset corrected by Reinhard Zumkeller, Jan 28 2015 STATUS approved

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Last modified May 7 20:36 EDT 2021. Contains 343652 sequences. (Running on oeis4.)