cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A220415 Table T(n,k)= floor(n/k)+ floor(k/n), n,k >0 read by antidiagonals.

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%I A220415 #19 Feb 16 2022 18:24:45
%S A220415 2,2,2,3,2,3,4,1,1,4,5,2,2,2,5,6,2,1,1,2,6,7,3,1,2,1,3,7,8,3,2,1,1,2,
%T A220415 3,8,9,4,2,1,2,1,2,4,9,10,4,2,1,1,1,1,2,4,10,11,5,3,2,1,2,1,2,3,5,11
%N A220415 Table T(n,k)= floor(n/k)+ floor(k/n), n,k >0 read by antidiagonals.
%H A220415 Boris Putievskiy, <a href="/A220415/b220415.txt">Rows n = 1..140 of triangle, flattened</a>
%H A220415 Boris Putievskiy, <a href="http://arxiv.org/abs/1212.2732">Transformations Integer Sequences And Pairing Functions</a>, arXiv:1212.2732 [math.CO], 2012.
%F A220415 a(n) = floor(A002260(n)/A004736(n))+floor(A004736(n)/A002260(n)) or
%F A220415 a(n) = floor((n-t*(t+1)/2)/((t*t+3*t+4)/2-n)) + floor(((t*t+3*t+4)/2-n)/(n-t*(t+1)/2)), where t=floor((-1+sqrt(8*n-7))/2).
%e A220415 The start of the sequence as triangle array read by rows:
%e A220415   2;
%e A220415   2,2;
%e A220415   3,2,3;
%e A220415   4,1,1,4;
%e A220415   5,2,2,2,5;
%e A220415   6,2,1,1,2,6;
%e A220415   ...
%o A220415 (Python)
%o A220415 t=int((math.sqrt(8*n-7) - 1)/ 2)
%o A220415 a = n-t*(t+1)/2
%o A220415 b= (t*t+3*t+4)/2-n
%o A220415 m= int(a/b)+int(b/a)
%Y A220415 Cf. A002260, A004736.
%K A220415 nonn,tabl
%O A220415 1,1
%A A220415 _Boris Putievskiy_, Dec 21 2012