A193492 Put the natural numbers together without spaces and read them four at a time advancing one space each time.

1234, 2345, 3456, 4567, 5678, 6789, 7891, 8910, 9101, 1011, 111, 1112, 1121, 1213, 2131, 1314, 3141, 1415, 4151, 1516, 5161, 1617, 6171, 1718, 7181, 1819, 8192, 1920, 9202, 2021, 212, 2122, 1222, 2223, 2232, 2324, 3242, 2425, 4252, 2526, 5262, 2627, 6272

Offset: 1

Author

Reinhard Zumkeller, Jul 28 2011

Keywords

• nonn
• base

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A136414, A193431, A193493.

Programs

Haskell

a193492 n = a193492_list !! (n-1)
a193492_list = f a007376_list where
   f xs'@(x:xs) = ((foldl (\u v -> 10*u + v) 0) $ take 4 xs') : f xs

Mathematica

FromDigits/@Partition[Flatten[IntegerDigits/@Range[30]],4,1] (* Harvey P. Dale, Aug 19 2012 *)

Formula

a(n) = 10*(10*(10*A007376(n)+A007376(n+1))+A007376(n+2))+A007376(n+3).