A063970 a(1) = 2; for n>1, write down all divisors of the previous term in order of magnitude.

2, 12, 1234612, 1247915831639077814156283086536173061234612

Offset

1,1

Comments

The next term has 3104 digits. - Harvey P. Dale, May 28 2017

Links

Table of n, a(n) for n=1..4.

Example

Divisors of a(3)={1, 2, 4, 79, 158, 316, 3907, 7814, 15628, 308653, 617306, 1234612}

Mathematica

NestList[FromDigits[Flatten[IntegerDigits/@Divisors[#]]]&, 2, 4] (* Harvey P. Dale, May 28 2017 *)

Prog

(Python)
from sympy import divisors
def aupton(terms):
  alst = [2]
  for n in range(2, terms+1):
    alst.append(int("".join(str(d) for d in divisors(alst[-1]))))
  return alst
print(aupton(4)) # Michael S. Branicky, Feb 12 2021

Crossrefs

Cf. A006919, A056938.

Sequence in context: A038081 A291258 A027737 * A309864 A130769 A128033

Adjacent sequences: A063967 A063968 A063969 * A063971 A063972 A063973

Keyword

nonn,base

Author

Labos Elemer, Sep 05 2001

Extensions

Next term has more than 3000 decimal digits.

Status

approved