A121610 - OEIS

%I #4 Mar 30 2012 18:50:55

%S 44,46,48,49,64,66,68,69,84,86,88,94,96,98,99,104,106,108,124,126,128,

%T 129,144,146,148,154,156,158,159,164,166,168,169,184,186,188,189,204,

%U 206,208,209,214,216,218,219,224,226,228,244,246,248,249,254,256,258

%N Composite numbers that can be written as concatenation of two composite numbers in decimal representation.

%e A002808(328) = 408 = 40*10+8 = A002808(27)*10+A002808(3),

%e therefore 408 is a term: a(99) = 408;

%e A002808(331) = 412 = 4*100+12 = A002808(1)*100+A002808(6),

%e therefore 412 is a term: a(100) = 412.

%Y Cf. A121609, A105184, A121608.

%K nonn,base

%O 1,1

%A _Reinhard Zumkeller_, Aug 10 2006