A104738 Positions of records in A104706.

1, 2, 3, 5, 6, 9, 11, 15, 17, 21, 24, 29, 30, 39, 41, 51, 54, 59, 66, 75, 77, 87, 96, 105, 107, 120, 129, 137, 141, 161, 165, 180, 186, 201, 209, 221, 227, 249, 255, 270, 285, 306, 311, 324, 336, 359, 366, 390, 401, 420, 435, 459, 465, 495, 501, 527, 534

Offset: 1

Author

Zak Seidov, Mar 21 2005

Keywords

• nonn

Comments

The entries in this sequence are the same as the partial sums of the independently derived A204539, for reasons unknown at present. - Colm Fagan, Jan 23 2012

Links

• Robert Israel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A104706, A104737, A104739, A204539.

See A002491 for a conjectured connection to this sequence.

Programs

BASIC

n=n+1; temp1=n^2; for k=(n-1) step -1 to 2; temp2=int(temp1/k); temp1=k*temp2; if int((temp2+k)/2))*2<>(temp2+k) then temp1=temp1-k; next k; a(n-1)=temp1/4 ' Colm Fagan, Nov 08 2015

MATLAB

function [ A ] = A104738( N )
% Produce a(1) : a(N)
M = N;
R = [1:M];
v = 1;
A = 1;
count = 1;
n = 1;
while count < N
    n = n+1;
    if 2*R(1)+1 > M
        R = [R, (M+1):M+N];
    end
    R = [R(2:2*R(1)+1), R(1), R((2*R(1)+2) : M)];
    if R(1) > v
        A = [A, n];
        v = R(1);
        count = count+1;
    end
end
end;
A104738(100)

Mathematica

A104706 = NestList[Rest[Insert[#, #[[1]], 2 + 2 #[[1]]]]&, Range[m = 1000], m][[All, 1]];
rec = 0; Reap[For[k = 1, k <= Length[A104706], k++, ak = A104706[[k]]; If[ak > rec, rec = ak; Sow[k]]]][[2, 1]] (* Jean-François Alcover, Apr 11 2019, after Birkas Gyorgy in A104706 *)

PARI

a(n) = {n++; temp1 = n^2; forstep (k= n-1, 2, -1, temp2 = temp1\k; temp1 = k*temp2; if (((temp2+k)\2)*2 != (temp2+k), temp1 -= k)); temp1/4;} \\ after Basic; Michel Marcus, Dec 04 2015

Extensions

Extended by Ray Chandler, Jan 19 2012