A054264 Concatenation of composite numbers between the n-th prime and the following prime.

4, 6, 8910, 12, 141516, 18, 202122, 2425262728, 30, 3233343536, 383940, 42, 444546, 4849505152, 5455565758, 60, 6263646566, 686970, 72, 7475767778, 808182, 8485868788, 90919293949596, 9899100, 102, 104105106, 108, 110111112

Offset: 2

Author

Patrick De Geest, Apr 15 2000

Keywords

• nonn
• base
• easy

Links

• Andrew Howroyd, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A046933, A054265, A054266, A054267, A054268.

Programs

Mathematica

FromDigits[Flatten[IntegerDigits/@(Range[#[[1]]+1,#[[2]]-1])]]&/@Partition[ Prime[Range[2,30]],2,1] (* Harvey P. Dale, Mar 04 2014 *)

PARI

a(n)=my(r=prime(n)+1); fromdigits(concat(vector(nextprime(r)-r, i, digits(r+i-1)))) \\ Andrew Howroyd, Aug 14 2024

Extensions

Offset changed and name edited by Andrew Howroyd, Aug 14 2024