A037284 Replace n with concatenation of its odd divisors >1.

0, 0, 3, 0, 5, 3, 7, 0, 39, 5, 11, 3, 13, 7, 3515, 0, 17, 39, 19, 5, 3721, 11, 23, 3, 525, 13, 3927, 7, 29, 3515, 31, 0, 31133, 17, 5735, 39, 37, 19, 31339, 5, 41, 3721, 43, 11, 3591545, 23, 47, 3, 749, 525, 31751

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base
• easy

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A182469, A209229, A037277, A037283, A037285.

Programs

Haskell

a037284 n
   | a209229 n == 1 = 0
   | otherwise      = read $ concat $ (map show) $ tail $ a182469_row n
-- Reinhard Zumkeller, May 01 2012

Mathematica

Array[FromDigits[Flatten[IntegerDigits/@Rest[Select[Divisors[#], OddQ]]]]&, 60] (* Harvey P. Dale, Mar 03 2014 *)

Python

from sympy import divisors
def a(n):
  odd_divisors_gt1 = [d for d in divisors(n)[1:] if d%2 == 1]
  if len(odd_divisors_gt1) == 0: return 0
  else: return int("".join(str(d) for d in odd_divisors_gt1))
print([a(n) for n in range(1, 52)]) # Michael S. Branicky, Dec 31 2020

Extensions

a(36) corrected by Reinhard Zumkeller, May 01 2012