cp's OEIS Frontend

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

%I A181497 #19 Sep 08 2022 08:45:54
%S A181497 0,1,3,7,11,19,27,35,43,59,75,91,107,123,139,155,171,203,235,267,299,
%T A181497 331,363,395,427,459,491,523,555,587,619,651,683,747,811,875,939,1003,
%U A181497 1067,1131,1195,1259,1323,1387,1451,1515,1579,1643,1707,1771,1835,1899
%N A181497 a(n) is the smallest m such that A056753(m) = 2*n + 1.
%C A181497 A056753(a(n)) = A005408(n) and A056753(m) < A005408(n) for m < a(n).
%H A181497 Alois P. Heinz, <a href="/A181497/b181497.txt">Table of n, a(n) for n = 0..10000</a>
%p A181497 a:= proc(n) option remember; `if`(n<2, n,
%p A181497       (h-> 2*a(n-h)-1+2*a(h))(iquo(n, 2)))
%p A181497     end:
%p A181497 seq(a(n), n=0..60);  # _Alois P. Heinz_, Jul 26 2019
%t A181497 a[n_] := a[n] = If[n < 2, n, 2 a[n-#] - 1 + 2 a[#]&[Quotient[n, 2]]];
%t A181497 a /@ Range[0, 60] (* _Jean-François Alcover_, Nov 04 2020, after _Alois P. Heinz_ *)
%o A181497 (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
%K A181497 nonn,look
%O A181497 0,3
%A A181497 _Reinhard Zumkeller_, Oct 24 2010