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 A175794 a(n) = Sum_{k=1..n} (-1)^A001620(k). 2
 -1, -2, -3, -2, -3, -4, -3, -2, -1, -2, -1, -2, -3, -4, -3, -2, -1, 0, 1, 2, 3, 2, 1, 2, 3, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 9, 10, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 2, 1, 0, -1, 0, 1, 2, 1, 0, 1, 0, 1, 0, 1, 2, 3, 4, 5, 6, 5, 4, 5, 6, 5, 4, 3, 4, 5, 6, 7, 6, 7, 6, 5, 6, 5, 6, 5, 6, 7, 6, 7, 6, 5, 4, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Table of n, a(n) for n = 1..10000 EXAMPLE a(6) = -4 is in the sequence because -4 = (-1)^5 + (-1)^7 + (-1)^7 + (-1)^2 + (-1)^1 + (-1)^5 MAPLE with(numtheory):T:=array(1..201): Digits:=200:nn:=10^200:a:=floor(evalf(gamma(0))*nn): n:=a:l:=length(n):n0:=n:s:=0:for m from 1 to l do:q:=n0:u:=irem(q, 10):v:=iquo(q, 10):n0:=v :T[m]:=u:od: for p from l to 1 by -1 do:s:=s+(-1)^T[p]: printf(`%d, `, s):od: MATHEMATICA Rest@ FoldList[ Plus, 0, (-1)^First@ RealDigits[EulerGamma, 10, 200]] (* or *) Accumulate[(-1)^RealDigits[EulerGamma, 10, 100][[1]]] (* Harvey P. Dale, May 11 2014 *) CROSSREFS A001620 is the decimal expansion of Euler's constant (or Euler-Mascheroni constant) gamma. Sequence in context: A243519 A278102 A106383 * A324389 A105500 A288569 Adjacent sequences:  A175791 A175792 A175793 * A175795 A175796 A175797 KEYWORD sign,obsc,less,base AUTHOR Michel Lagneau, Sep 06 2010 STATUS approved

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Last modified March 18 11:15 EDT 2019. Contains 321283 sequences. (Running on oeis4.)