A123739 - OEIS

A123739

Partial sums of (-1)^floor(n*e).

1, 0, 1, 2, 1, 2, 1, 0, 1, 0, -1, 0, -1, 0, 1, 0, 1, 2, 1, 2, 1, 0, 1, 0, -1, 0, -1, 0, 1, 0, 1, 2, 1, 2, 1, 0, 1, 0, 1, 2, 1, 2, 3, 2, 3, 2, 1, 2, 1, 0, 1, 0, 1, 2, 1, 2, 3, 2, 3, 2, 1, 2, 1, 0, 1, 0, 1, 2, 1, 2, 3, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 4, 3, 4, 3, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 4, 3, 4, 3, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 2, 1, 2, 1, 0, 1, 0, 1, 2, 1, 2, 3, 2, 3, 2, 1, 2, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

Kevin O'Bryant, Bruce Reznick, and Monika Serbinowska, Almost alternating sums, Amer. Math. Monthly, Vol. 113 (October 2006), 673-688.

MATHEMATICA

Rest[FoldList[Plus, 0, (-1)^Floor[E*Range[120]]]]

Accumulate[(-1)^Floor[E Range[200]]] (* Harvey P. Dale, May 06 2022 *)

PROG

(PARI) vector(50, n, sum(j=1, n, (-1)^(j\exp(-1))) ) \\ G. C. Greubel, Sep 05 2019

(Magma) [&+[(-1)^Floor(j*Exp(1)): j in [1..n]]: n in [1..130]]; // G. C. Greubel, Sep 05 2019

(Sage) [sum((-1)^floor(j*exp(1)) for j in (1..n)) for n in (1..130)] # G. C. Greubel, Sep 05 2019

CROSSREFS

Cf. A123724 (sum for 2^(1/3)), A123737 (sum for sqrt(2)), A123738 (sum for pi).

Sequence in context: A234694 A091704 A175799 * A165575 A165582 A165472

Adjacent sequences: A123736 A123737 A123738 * A123740 A123741 A123742

KEYWORD

easy,sign

AUTHOR

T. D. Noe, Oct 11 2006

STATUS

approved