A113526 Define the first two terms to be 1 and 3. All the other terms are obtained by concatenating the two previous terms.

1, 3, 13, 313, 13313, 31313313, 1331331313313, 313133131331331313313, 1331331313313313133131331331313313, 3131331313313313133131331331313313313133131331331313313

Offset: 1

Author

Parthasarathy Nambi, Jan 12 2006

Keywords

• base
• nonn

Examples

			The third term is 13 which is obtained by concatenating the two previous terms 1 and 3.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..16

Crossrefs

Cf. A008352.

Programs

Mathematica

a[1] = 1; a[2] = 3; a[n_] := FromDigits@ Join[IntegerDigits@a[n - 2], IntegerDigits@a[n - 1]]; Array[a, 10] (* Robert G. Wilson v *)
nxt[{a_,b_}]:={b,FromDigits[Join[Flatten[IntegerDigits/@{a,b}]]]}; NestList[nxt,{1,3},10][[All,1]] (* Harvey P. Dale, May 15 2017 *)

Extensions

More terms from Robert G. Wilson v, Jan 18 2006