A154513 The prime(n)-th digit of the concatenated composites.

6, 8, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 9, 9, 9, 9, 1, 4, 6, 0, 1, 1, 1, 7, 1, 1, 1, 3, 8, 3, 1, 5, 1, 1, 1, 1, 1, 1, 1, 3, 5, 1, 8, 1, 8, 1, 0, 1, 7, 0, 1, 5, 1, 1, 2, 5, 8, 2, 2, 5, 2, 9, 2, 4, 2, 8, 0, 2, 2, 8, 2, 1, 2, 2, 2, 2, 6, 2, 2, 2, 5, 2, 5, 2, 2, 2, 5

Offset

1,1

Comments

The concatenated composites are A129808, the initial 1 removed.

Links

Table of n, a(n) for n=1..105.

Formula

a(n) = A129808(prime(n)+1).

Maple

a129808 := [1 ] : for n from 4 to 400 do if not isprime(n) then a129808 := [op(a129808), op(ListTools[Reverse](convert(n, base, 10))) ] ; fi; od:
for n from 1 do p := ithprime(n) ; printf("%d, ", op(p+1, a129808) ) ; od: # R. J. Mathar, Aug 03 2009

Mathematica

nn=700; With[{c=Flatten[IntegerDigits/@Complement[Range[4, nn], Prime[Range[ PrimePi[nn]]]]]}, Flatten[Table[Take[c, {n, n}], {n, Prime[Range[ PrimePi[ nn]]]}]]] (* Harvey P. Dale, Nov 22 2013 *)

Crossrefs

Cf. A000040, A002808, A154513, A154520.

Sequence in context: A083727 A111838 A197479 * A348435 A239804 A195716

Adjacent sequences: A154510 A154511 A154512 * A154514 A154515 A154516

Keyword

nonn,base

Author

Juri-Stepan Gerasimov, Jan 11 2009

Extensions

Edited and corrected by R. J. Mathar, Aug 03 2009

Status

approved