A181497 a(n) is the smallest m such that A056753(m) = 2*n + 1.

0, 1, 3, 7, 11, 19, 27, 35, 43, 59, 75, 91, 107, 123, 139, 155, 171, 203, 235, 267, 299, 331, 363, 395, 427, 459, 491, 523, 555, 587, 619, 651, 683, 747, 811, 875, 939, 1003, 1067, 1131, 1195, 1259, 1323, 1387, 1451, 1515, 1579, 1643, 1707, 1771, 1835, 1899

Offset: 0

Author

Reinhard Zumkeller, Oct 24 2010

Keywords

• nonn
• look

Comments

A056753(a(n)) = A005408(n) and A056753(m) < A005408(n) for m < a(n).

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000

Programs

Magma

T:=[]; S:=[ 0: n in [1..2000] ]; k:=1; p:=Position(S, 0, 1); while p gt 0 do for j in [p..#S by k+1] do if S[j] eq 0 then S[j]:=k; else break; end if; end for; f:=p; Append(~T, p-1); p:=Position(S, 0, f); k+:=2; end while; T; // Klaus Brockhaus, Oct 25 2010

Maple

a:= proc(n) option remember; `if`(n<2, n,
      (h-> 2*a(n-h)-1+2*a(h))(iquo(n, 2)))
    end:
seq(a(n), n=0..60);  # Alois P. Heinz, Jul 26 2019

Mathematica

a[n_] := a[n] = If[n < 2, n, 2 a[n-#] - 1 + 2 a[#]&[Quotient[n, 2]]];
a /@ Range[0, 60] (* Jean-François Alcover, Nov 04 2020, after Alois P. Heinz *)