A078261 a(n) = numerator(N) where N = 0.246...(2n) is the concatenation of the first n even numbers after the decimal point.
1, 6, 123, 617, 24681, 6170253, 1234050607, 30851265177, 12340506070809, 123405060708091, 123405060708091011, 1542563258851137639, 1234050607080910111213, 61702530354045505560657, 2468101214161820222426283, 308512651770227527803285379, 123405060708091011121314151617
Offset: 1
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..351
Programs
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Maple
a:= n-> (t-> numer(t/10^length(t)))(parse(cat(2*i$i=1..n))): seq(a(n), n=1..17); # Alois P. Heinz, Jun 25 2025
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PARI
a(n) = {my(s = ""); for (k=1, n, s = concat(s, Str(2*k))); numerator(eval(s)/10^(#s));} \\ Michel Marcus, Jan 15 2019
Extensions
More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003
More terms from Michel Marcus, Jan 15 2019