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Revision History for A006338 (Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A006338 An "eta-sequence": floor((n+1)*sqrt(2) + 1/2) - floor(n*sqrt(2) + 1/2).
(history; published version)
#33 by Charles R Greathouse IV at Thu Sep 08 08:44:34 EDT 2022
PROG

(MAGMAMagma) [Floor((n+1)*Sqrt(2)+1/2) - Floor(n*Sqrt(2)+1/2): n in [1..30]]; // G. C. Greubel, Nov 18 2017

Discussion
Thu Sep 08 08:44
OEIS Server: https://oeis.org/edit/global/2944
#32 by Harvey P. Dale at Fri Dec 10 19:29:46 EST 2021
STATUS

editing

approved

#31 by Harvey P. Dale at Fri Dec 10 19:29:42 EST 2021
MATHEMATICA

Differences[Table[Floor[n Sqrt[2]+1/2], {n, 120}]] (* Harvey P. Dale, Dec 10 2021 *)

STATUS

approved

editing

#30 by Susanna Cuyler at Sat Nov 18 20:55:39 EST 2017
STATUS

proposed

approved

#29 by Jon E. Schoenfield at Sat Nov 18 20:17:16 EST 2017
STATUS

editing

proposed

#28 by Jon E. Schoenfield at Sat Nov 18 20:17:11 EST 2017
NAME

An "eta-sequence": [ (": floor((n+1)*sqrt(2) + () + 1/2) ] - [ ) - floor(n*sqrt(2) + () + 1/2) ].).

COMMENTS

Presumably this is the same as the following sequence from Hofstadter's book: the number of triangular numbers between each successive pair of squares. More precisely, a(n) is the number of triangular numbers T such that n^2 <= T < (n+1)^2. E.g. ., a(3) = 2 because 3^2 <= T < 4^2 permits T(4) = 10 and T(5) = 15 and no other triangular number. - Hugo van der Sanden, May 03 2005.

STATUS

proposed

editing

#27 by G. C. Greubel at Sat Nov 18 17:52:27 EST 2017
STATUS

editing

proposed

#26 by G. C. Greubel at Sat Nov 18 17:51:57 EST 2017
FORMULA

a(n) = floor((n+1)*sqrt(2) + 1/2) - floor(n*sqrt(2) + 1/2). - G. C. Greubel, Nov 18 2017

PROG

(PARI) for(n=1, 30, print1(floor((n+1)*sqrt(2) + 1/2) - floor(n*sqrt(2) + 1/2), ", ")) \\ G. C. Greubel, Nov 18 2017

(MAGMA) [Floor((n+1)*Sqrt(2)+1/2) - Floor(n*Sqrt(2)+1/2): n in [1..30]]; // G. C. Greubel, Nov 18 2017

STATUS

approved

editing

#25 by Bruno Berselli at Tue Nov 24 09:48:58 EST 2015
STATUS

reviewed

approved

#24 by Joerg Arndt at Tue Nov 24 09:02:10 EST 2015
STATUS

proposed

reviewed

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Last modified August 29 00:59 EDT 2024. Contains 375508 sequences. (Running on oeis4.)