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A076816 Squares modulo triangular numbers: n^2 minus the greatest triangular number smaller than or equal to n^2. 2
0, 0, 1, 3, 1, 4, 0, 4, 9, 3, 9, 1, 8, 16, 6, 15, 3, 13, 24, 10, 22, 6, 19, 1, 15, 30, 10, 26, 4, 21, 39, 15, 34, 8, 28, 0, 21, 43, 13, 36, 4, 28, 53, 19, 45, 9, 36, 64, 26, 55, 15, 45, 3, 34, 66, 22, 55, 9, 43, 78, 30, 66, 16, 53, 1, 39, 78, 24, 64, 8, 49, 91, 33, 76, 16, 60, 105, 43 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
FORMULA
a(n)=n^2-floor(sqrt(2*n^2+1/4)-1/2)*floor(sqrt(2*n^2+1/4)+1/2)/2
MAPLE
seq(n^2-floor(sqrt(2*n^2+1/4)-1/2)*floor(sqrt(2*n^2+1/4)+1/2)/2, n=0..100);
MATHEMATICA
smt[n_]:=Module[{x=Floor[(Sqrt[1+8n]-1)/2]}, n-(x(x+1))/2]; smt/@(Range[ 0, 80]^2) (* Harvey P. Dale, May 12 2014 *)
CROSSREFS
Cf. A064784.
Sequence in context: A123730 A143317 A130540 * A021765 A267187 A274716
KEYWORD
nonn,easy
AUTHOR
Floor van Lamoen, Oct 17 2002
STATUS
approved

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Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)