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A175213 a(n)= a(r)+a(s) ; (r+s)<=n ; r=(floor(sqrt(n-1)))^2 ; s=n-(floor(sqrt(n)))^2. 1
1, 2, 4, 6, 3, 5, 7, 9, 6, 4, 6, 8, 10, 7, 9, 11, 5, 7, 9, 11, 8, 10, 12, 14, 11, 6, 8, 10, 12, 9, 11, 13, 15, 12, 10, 12, 7, 9, 11, 13, 10, 12, 14, 16, 13, 11, 13, 15, 17, 8, 10, 12, 14, 11, 13, 15, 17, 14, 12, 14, 16, 18, 15, 17, 9, 11, 13, 15, 12, 14, 16, 18, 15, 13, 15, 17, 19, 16 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Ivan Neretin, Table of n, a(n) for n = 0..1000

EXAMPLE

a(0)=1, a(1)=a(0)+a(0)=2, a(2)=a(1)+a(1)=4, a(3)=a(1)+a(2)=6, a(4)=a(1)+a(0)=3, a(5)=a(4)+a(1)=5, a(6)=a(4)+a(2)=7, a(7)=a(4)+a(3)=9, a(8)=a(4)+a(4)=6, a(9)=a(4)+a(0)=4, a(10)=a(9)+a(1)=6, ...

MAPLE

A175213 := proc(n) option remember; local r, s ; if n = 0 then 1 ; else r := (floor(sqrt(n-1)))^2 ; s := n-(floor(sqrt(n)))^2 ; procname(r)+procname(s) ; end if; end proc: seq(A175213(n), n=0..100) ; # R. J. Mathar, Aug 24 2010

MATHEMATICA

Fold[Append[#1, #1[[Floor[Sqrt[#2 - 1]]^2 + 1]] + #1[[#2 - Floor[Sqrt[#2]]^2 + 1]]] &, {1}, Range@77] (* Ivan Neretin, Sep 03 2015 *)

CROSSREFS

Sequence in context: A061504 A077179 A076179 * A104492 A331522 A075075

Adjacent sequences:  A175210 A175211 A175212 * A175214 A175215 A175216

KEYWORD

easy,nonn

AUTHOR

Ctibor O. Zizka, Mar 06 2010

EXTENSIONS

More terms from R. J. Mathar, Aug 24 2010

STATUS

approved

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Last modified February 25 11:26 EST 2020. Contains 332233 sequences. (Running on oeis4.)