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A176558 a(n) is the reverse concatenation of divisors of n. 34
1, 21, 31, 421, 51, 6321, 71, 8421, 931, 10521, 111, 1264321, 131, 14721, 15531, 168421, 171, 1896321, 191, 20105421, 21731, 221121, 231, 2412864321, 2551, 261321, 27931, 28147421, 291, 30151065321, 311, 32168421, 331131, 341721, 35751, 361812964321, 371 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Union of A089374(n) for n >= 1 and A175354(n) for n >= 2. - Jonathan Vos Post, Apr 17 2011

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..50000

EXAMPLE

For n=12; divisors of 12: 1,2,3,4,6,12; a(12)=1264321 (reverse concatenation).

MAPLE

a:= n-> parse(cat(sort([numtheory[divisors](n)[]], `>`)[])):

seq(a(n), n=0..40);  # Alois P. Heinz, Dec 31 2020

MATHEMATICA

Table[FromDigits@ Flatten@ Map[IntegerDigits, Reverse@ Divisors@ n], {n, 34}] (* Michael De Vlieger, Jan 23 2017 *)

PROG

(PARI) a(n) = {s = ""; fordiv(n, d, s = concat(Str(d), s)); eval(s); } \\ Michel Marcus, Feb 16 2015

(Python)

from sympy import divisors

def a(n): return int("".join(str(d) for d in divisors(n)[::-1]))

print([a(n) for n in range(1, 35)]) # Michael S. Branicky, Dec 31 2020

CROSSREFS

Cf. A089374, A175354, A175355, A176588, A176589.

Sequence in context: A032013 A324489 A256824 * A243360 A068657 A068671

Adjacent sequences:  A176555 A176556 A176557 * A176559 A176560 A176561

KEYWORD

nonn,base

AUTHOR

Jaroslav Krizek, Apr 20 2010

EXTENSIONS

More terms from Charles R Greathouse IV, Apr 23 2010

Corrected by Jaroslav Krizek, Apr 26 2010

Edited by Charles R Greathouse IV, Apr 30 2010

STATUS

approved

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Last modified April 14 01:49 EDT 2021. Contains 342941 sequences. (Running on oeis4.)