A392407 - OEIS

%I #29 Feb 16 2026 13:16:23

%S 4,23,111,1363,24408,17695288,6824557154,7725215723631,7725215723632,

%T 12394845542349305,32487681032537859566,

%U 1067849037636462036996360431525

%N Indices in Recamán's sequence A005132 which are the result of a record number of subtraction steps.

%C A393285 gives corresponding values of A005132.

%C a(14) > 10^612.

%H Benjamin Chaffin, <a href="/A392407/b392407.txt">Table of n, a(n) for n = 1..13</a>

%e Let R(n) = n-th term of Recamán's sequence (A005132). R(108)..R(111) are 370, 261, 151, 40; so R(111)=40 is the result of three consecutive subtraction steps, and is the first such R(n). Thus a(3) = 111.

%Y Cf. A005132, A393285 (corresponding terms), A390717 (record addition indices), A393284 (record addition terms), A057165 (addition steps), A057166 (subtraction steps).

%K nonn

%O 1,1

%A _Benjamin Chaffin_, Feb 09 2026