A134794 Concatenation of next n composite numbers.

4, 68, 91012, 14151618, 2021222425, 262728303233, 34353638394042, 4445464849505152, 545556575860626364, 65666869707274757677, 7880818284858687889091

Offset: 1

Author

Omar E. Pol, Nov 26 2007

Keywords

• base
• easy
• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A053067, A133013. Composite numbers: A002808.

Programs

Mathematica

cc[x_]:=FromDigits[Flatten[IntegerDigits/@x]]; Module[{nn= 100,cmps,tr,len},cmps = Select[Range[nn],CompositeQ];len=Length[cmps];tr = Floor[ (Sqrt[1+8 len]-1)/2];cc/@TakeList[cmps,Range[tr]]] (* Harvey P. Dale, Sep 26 2021 *)