A175944 - OEIS

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

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OFFSET

1,2

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]

LINKS

Table of n, a(n) for n=1..75.

FORMULA

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

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 *)

PROG

(Haskell)

a175944 n = a175944_list !! (n-1)

a175944_list =

concat $ zipWith ($) (map replicate a018252_list) a018252_list