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 A061387 #10 Mar 17 2023 14:42:35 %S A061387 4,17,26,35,44,53,62,71,80,129,138,147,156,165,174,183,192,219,228, %T A061387 237,246,255,264,273,282,291,309,318,327,336,345,354,363,372,381,390, %U A061387 408,417,426,435,444,453,462,471,480,507,516,525,534,543,552,561,570,606 %N A061387 Sum of digits = 4 times number of digits. %e A061387 147 is a term as the arithmetic mean of the digits is (1+4+7)/3 = 4. %o A061387 (Magma) [ n: n in [1..610] | &+Intseq(n) eq 4*#Intseq(n) ]; // _Bruno Berselli_, Jun 30 2011 %Y A061387 Cf. A061383, A061384, A061385, A061386, A061388, A061423, A061424, A061425. %K A061387 nonn,base,easy %O A061387 1,1 %A A061387 _Amarnath Murthy_, May 03 2001 %E A061387 More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001