A191992 Concatenation of n and the n-th composite number.

14, 26, 38, 49, 510, 612, 714, 815, 916, 1018, 1120, 1221, 1322, 1424, 1525, 1626, 1727, 1828, 1930, 2032, 2133, 2234, 2335, 2436, 2538, 2639, 2740, 2842, 2944, 3045, 3146, 3248, 3349, 3450, 3551, 3652, 3754, 3855, 3956, 4057, 4158, 4260, 4362, 4463, 4564, 4665, 4766, 4868, 4969, 5070, 5172, 5274, 5375, 5476

Offset

1,1

Links

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

Mathematica

Module[{upto=55, cmps, len}, cmps=Select[Range[10*upto], CompositeQ]; len= Min[ Length[ cmps], upto]; #[[1]]*10^IntegerLength[#[[2]]]+#[[2]]&/@ Thread[{ Range[ len], Take[cmps, len]}]] (* Harvey P. Dale, Dec 05 2016 *)

Prog

(PARI) n=0; for(k=4, 1e3, if(isprime(k), k++); print1(n++k", ")) \\ Charles R Greathouse IV, Jun 21 2011

Crossrefs

Cf. A045532, the prime analog of this sequence.

Cf. A246801, primes in this sequence.

Sequence in context: A176274 A344872 A240227 * A082773 A242395 A112772

Adjacent sequences: A191989 A191990 A191991 * A191993 A191994 A191995

Keyword

nonn,base

Author

Kausthub Gudipati, Jun 20 2011

Status

approved