A377748 - OEIS

%I #32 Nov 18 2024 18:27:46

%S 0,0,0,0,4,4,4,4,12,12,22,22,34,34,48,48,64,64,64,64,84,84,106,129,

%T 129,154,154,181,181,210,210,241,241,241,241,276,276,313,351,351,391,

%U 391,433,433,477,477,523,523,571,571,621,621,673,673,727,727,783,783,841,841

%N a(n) = (A000217(n) - A005132(n))/2.

%C a(n) is the sum of the down steps in the first n terms of Recamán's sequence A005132.

%H <a href="/index/Rea#Recaman">Index entries for sequences related to Recamán's sequence</a>

%F a(n) = Sum_{k=1..n} max(0, -A160356(k)).

%e a(0) = (0-0)/2, a(1) = (1-1)/2, a(2) = (3-3)/2, a(3) = (6-6)/2, a(4) = (10-2)/2, a(5) = (15-7)/2 ... .

%Y Cf. A000217, A005132, A160356.

%K nonn

%O 0,5

%A _Paul Curtz_, Nov 06 2024