A379803 - OEIS

%I #21 Feb 12 2025 01:57:50

%S 2,8,-18,-32,50,72,-98,-128,-162,200,242,288,338,512,-578,722,800,882,

%T 968,-1058,1152,1250,1352,1458,-1568,1682,1800,1922,-2048,-2178,-2312,

%U 2450,2592,-2738,-2888,3042,3200,-3362,3528,-3698,-3872,4232,-4418,-4608,4802,-5000,5618,-6050,6272,-6498,7938,-8192,8712,-8978,-9248,9522,-9800

%N A377091(k) for k in A379802.

%C These are the values of the terms in A377091 that are immediately followed by their negatives.

%H Rémy Sigrist, <a href="/A379803/b379803.txt">Table of n, a(n) for n = 1..10001</a> (first 209 terms from N. J. A. Sloane)

%H Rémy Sigrist, <a href="/A379803/a379803.txt">C++ program</a>

%e A377091(31) = -18 is immediately followed by A377091(32) = 18, so 31 is a term in A379802, and -18 is in the present sequence.

%t (* A377091list is defined at A377091 *)

%t #[[PositionIndex[Differences[Abs[#]]][0]]] & [A377091list[10000]] (* _Paolo Xausa_, Jan 22 2025 *)

%o (C++) // See Links se

%Y Cf. A377091, A379066, A379788-A379794, A379802, A379804, A380837.

%K sign

%O 1,1

%A _N. J. A. Sloane_, Jan 19 2025