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%I #35 Feb 16 2024 01:20:34
%S 2,24,246,2468,246810,24681012,2468101214,246810121416,24681012141618,
%T 2468101214161820,246810121416182022,24681012141618202224,
%U 2468101214161820222426,246810121416182022242628,24681012141618202224262830,2468101214161820222426283032
%N a(n) is the concatenation of the first n positive even numbers.
%D H. Ibstedt, A Few Smarandache Sequences, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, 170-183.
%D F. Smarandache, "Collected Papers", Vol. II, Tempus Publ. Hse., Bucharest, Romania, 1996.
%D S. Smarandoiu, Convergence of Smarandache continued fractions, Abstract 96T-11-195, Abstracts Amer. Math. Soc., 17 (No. 4, 1996), 680.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ConsecutiveNumberSequences.html">Consecutive Number Sequences</a>
%F Lim_{n->oo} A019519(n)/a(n) = 0 (see A067095). - _Bernard Schott_, Dec 18 2021
%t Table[FromDigits[Flatten[IntegerDigits/@(2Range[n])]],{n,20}] (* _Harvey P. Dale_, Mar 24 2013 *)
%o (Python)
%o def a(n): return int("".join(str(2*i) for i in range(1, n+1)))
%o print([a(n) for n in range(1, 17)]) # _Michael S. Branicky_, Dec 18 2021
%Y Cf. A019519 (similar, with odd numbers), A067095, A108728.
%K base,nonn,easy,less
%O 1,1
%A R. Muller
%E More terms from _Erich Friedman_
%E More terms from _Harvey P. Dale_, Mar 24 2013