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A038444 Sums of 2 distinct powers of 10. 16
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

Olivier Gérard

EXTENSIONS

Offset corrected by Reinhard Zumkeller, Jan 28 2015

STATUS

approved

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Last modified May 27 11:14 EDT 2017. Contains 287204 sequences.