cp's OEIS Frontend

A109400 For all k: the first k numbers followed by the first k primes.

%I A109400 #14 Jun 23 2015 10:14:48
%S A109400 1,2,1,2,2,3,1,2,3,2,3,5,1,2,3,4,2,3,5,7,1,2,3,4,5,2,3,5,7,11,1,2,3,4,
%T A109400 5,6,2,3,5,7,11,13,1,2,3,4,5,6,7,2,3,5,7,11,13,17,1,2,3,4,5,6,7,8,2,3,
%U A109400 5,7,11,13,17,19,1,2,3,4,5,6,7,8,9,2,3,5,7,11,13,17,19,23
%N A109400 For all k: the first k numbers followed by the first k primes.
%C A109400 a(k*(k-1) + m) = a(A002378(k-1) + m) = m for 1<=m<=k;
%C A109400 a(k^2 + m) = a(A000290(k) + m) = A000040(m) for 1<=m<=k;
%C A109400 see A109401 for number of primes and A109402 for partial sums.
%H A109400 Reinhard Zumkeller, <a href="/A109400/b109400.txt">Table of n, a(n) for n = 1..10000</a>
%e A109400 1, 2; 1 2, 2 3; 1 2 3, 2 3 5; 1 2 3 4, 2 3 5 7; 1 2 ...
%t A109400 With[{prs=Prime[Range[20]]},Flatten[Table[{Range[n],Take[prs,n]},{n,10}]]] (* _Harvey P. Dale_, Dec 08 2011 *)
%o A109400 (Haskell)
%o A109400 a109400 n = a109400_list !! (n-1)
%o A109400 a109400_list = concat $ zipWith (++) a002260_tabl a037126_tabl
%o A109400 -- _Reinhard Zumkeller_, Jun 23 2015, Dec 11 2011
%Y A109400 Cf. A002260, A037126, A082500, A000040.
%K A109400 nonn
%O A109400 1,2
%A A109400 _Reinhard Zumkeller_, Jun 27 2005