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A220415 Table T(n,k)= floor(n/k)+ floor(k/n), n,k >0 read by antidiagonals. 3
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, 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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Boris Putievskiy, Rows n = 1..140 of triangle, flattened

Boris Putievskiy, Transformations Integer Sequences And Pairing Functions arXiv:1212.2732 [math.CO]

FORMULA

a(n) = floor(A002260(n)/A004736(n))+floor(A004736(n)/A002260(n)) or

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).

EXAMPLE

The start of the sequence as triangle array read by rows:

2;

2,2;

3,2,3;

4,1,1,4;

5,2,2,2,5;

6,2,1,1,2,6;

. . .

PROG

(Python)

t=int((math.sqrt(8*n-7) - 1)/ 2)

a = n-t*(t+1)/2

b= (t*t+3*t+4)/2-n

m= int(a/b)+int(b/a)

CROSSREFS

Cf. A002260, A004736.

Sequence in context: A259194 A194344 A128435 * A286565 A219354 A026903

Adjacent sequences:  A220412 A220413 A220414 * A220416 A220417 A220418

KEYWORD

nonn,tabl

AUTHOR

Boris Putievskiy, Dec 21 2012

STATUS

approved

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Last modified August 23 11:24 EDT 2019. Contains 326222 sequences. (Running on oeis4.)