A078278 a(n) is the number from which if odd-positioned digits are deleted then one gets the concatenation of first n prime numbers, while if even-positioned digits are deleted then one gets reverse concatenation of first n prime numbers. Position of least significant digit is considered to be 1.

22, 2332, 253352, 27355372, 213157751312, 2133517117151332, 21375173111117351372, 213951771113113117751392, 2233517911171133117117952332, 22395273111911371173119127352392

Offset

1,1

Links

Table of n, a(n) for n=1..10.

Example

a(4) = 27355372: deleting alternate digits starting from the LSD leaves 2357. Deleting the other ones leaves 7532.

Crossrefs

Cf. A078279, A078280, A078281.

Sequence in context: A069222 A117990 A098130 * A231053 A078275 A200805

Adjacent sequences: A078275 A078276 A078277 * A078279 A078280 A078281

Keyword

base,nonn

Author

Amarnath Murthy, Nov 25 2002

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003

Status

approved