A218128 - OEIS

%I #13 Nov 01 2024 02:00:49

%S 0,1,7,10,16,34,70,82,88,124,127,160,172,199,217,250,268,340,352,358,

%T 379,394,397,442,451,520,538,574,619,622,664,682,700,718,754,775,802,

%U 829,844,871,880,970,973,988,1027,1078,1081,1117,1123,1171,1240,1252,1258

%N a(n) = (A090801(n+2) - 2)/4.

%C a(n) mod 9 appears to be always 1 or 7 (except the first term). Checked for the first 1000 terms.

%C a(n+2) - a(n+1) = 6, 3, 6, 18, 36, 12, 6, 36, 3, 33, 12, 27,... = (A090801(n+4) - A090801(n+3))/4 are multiples of 3.

%K nonn,changed

%O 0,3

%A _Paul Curtz_, Oct 21 2012