A037285 Replace n with concatenation of its nontrivial odd divisors.

0, 0, 0, 0, 0, 3, 0, 0, 3, 5, 0, 3, 0, 7, 35, 0, 0, 39, 0, 5, 37, 11, 0, 3, 5, 13, 39, 7, 0, 3515, 0, 0, 311, 17, 57, 39, 0, 19, 313, 5, 0, 3721, 0, 11, 35915, 23, 0, 3, 7, 525, 317, 13, 0, 3927, 511, 7, 319, 29, 0, 3515, 0, 31, 37921, 0, 513, 31133, 0, 17, 323, 5735, 0, 39, 0

Offset

1,6

Links

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

Prog

(Haskell)
import Data.List (delete)
a037285 n
| a209229 n == 1 = 0
| a010051 n == 1 = 0
| otherwise = read $ concat $ (map show) $ delete n $ tail $ a182469_row n
-- Reinhard Zumkeller, May 01 2012
(Python)
from sympy import divisors
def a(n):
  nontrivial_odd_divisors = [d for d in divisors(n)[1:-1] if d%2 == 1]
  if len(nontrivial_odd_divisors) == 0: return 0
  else: return int("".join(str(d) for d in nontrivial_odd_divisors))
print([a(n) for n in range(1, 70)]) # Michael S. Branicky, Dec 31 2020

Crossrefs

Cf. A182469, A209229, A010051, A106708, A037283, A037284.

Sequence in context: A222402 A222522 A091921 * A337981 A341761 A181787

Adjacent sequences: A037282 A037283 A037284 * A037286 A037287 A037288

Keyword

nonn,base,easy

Author

N. J. A. Sloane

Extensions

More terms from Erich Friedman

Status

approved