A078279 a(n) is the number from which if odd-positioned digits are deleted then one gets the concatenation of first n composite numbers, while if even-positioned digits are deleted then one gets reverse concatenation of first n composite numbers. Position of least significant digit is considered to be 1.

44, 4664, 486684, 49688694, 416089981604, 4162819019081624, 41648192110019281644, 416581941102112019481654, 4166819511041122114019581664, 41688196110511241142115019681684

Offset: 1

Author

Amarnath Murthy, Nov 25 2002

Keywords

• base
• nonn

Examples

			a(4) = 49688694: deleting alternate digits starting from the LSD leaves 4689. Deleting the other ones leaves 9864.
		

Crossrefs

Cf. A078278, A078280, A078281.

Extensions

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