This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A067278 #15 Mar 04 2025 02:46:41 %S A067278 0,3,6,11,15,19,22,27,32,36,39,45,51,59,67,74,81,90,98,106,112,121, %T A067278 130,141,151,161,170,181,192,202,208,217,226,237,247,257,266,277,288, %U A067278 298,303,311,319,329,338,347,355,365,375,384,389,397,405,415,424,433,441 %N A067278 a(n) = letters(n) + a(n-1); a(0) = 0. %F A067278 a(n) = A005589(n) + a(n-1). - _Michael S. Branicky_, Mar 03 2025 %e A067278 0 + one = 3, 3 + two = 6, 6 + three = 11, 11 + four = 15, 15 + five = 19, .... %Y A067278 Cf. A005589, A052360, A052362, A052363. %K A067278 easy,nonn,word %O A067278 0,2 %A A067278 _Scott A. Brown_, Feb 22 2002