A175944 1 appears once, n-th prime p appears p times.

1, 2, 2, 3, 3, 3, 5, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19

Offset: 1

Author

Juri-Stepan Gerasimov, Oct 27 2010

Keywords

• nonn
• easy

Comments

a(A014284(n)) = a(A175965(n)) = A018252(n). [Reinhard Zumkeller, Mar 18 2011]

This is how A063905 would have been reckoned at the beginning of the 20th century, taking the primes as given in A008578 instead of the way they are given in A000040. [Alonso del Arte, Sep 09 2011]

Crossrefs

Cf. A063905.

Cf. A005145.

Programs

Haskell

a175944 n = a175944_list !! (n-1)
a175944_list =
   concat $ zipWith ($) (map replicate a018252_list) a018252_list
-- Reinhard Zumkeller, Mar 18 2011

Mathematica

Join[{1}, Flatten[Table[Prime[n], {n, 8}, {Prime[n]}]]] (* Alonso del Arte, Sep 08 2011 based on Robert G. Wilson v's program for A002024 *)
Join[{1},Flatten[Table[PadRight[{},n,n],{n,Prime[Range[10]]}]]] (* Harvey P. Dale, May 16 2019 *)

Formula

a(1)=1, a(n)=A063905(n-1) for n>1.