A037283 Replace n with concatenation of its odd divisors.

1, 1, 13, 1, 15, 13, 17, 1, 139, 15, 111, 13, 113, 17, 13515, 1, 117, 139, 119, 15, 13721, 111, 123, 13, 1525, 113, 13927, 17, 129, 13515, 131, 1, 131133, 117, 15735, 139, 137, 119, 131339, 15, 141, 13721, 143, 111, 13591545, 123, 147, 13, 1749, 1525, 131751

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, A037278, A037284, A037285.

Programs

Haskell

a037283 = read . concat . (map show) . a182469_row :: Integer -> Integer
-- Reinhard Zumkeller, May 01 2012

Mathematica

dtn[ L_ ] := Fold[ 10#1+#2&, 0, L ] Array[ dtn[ Flatten[ Map[ IntegerDigits, Select[ Divisors[ # ], OddQ ] ] ] ]&, 50 ]
cod[n_]:=FromDigits[Flatten[IntegerDigits/@Select[Divisors[n],OddQ]]]; Array[cod,60] (* Harvey P. Dale, Jan 24 2014 *)

Python

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

Extensions

More terms from Erich Friedman