A036433 Number of divisors is a digit in the base 10 representation of n.

1, 2, 14, 23, 29, 34, 46, 63, 68, 74, 76, 78, 88, 94, 116, 127, 128, 134, 138, 141, 142, 143, 145, 146, 164, 182, 184, 186, 189, 194, 196, 211, 214, 223, 227, 229, 233, 236, 238, 239, 241, 247, 248, 249, 251, 254, 257, 258, 261, 263, 268, 269, 271, 274, 277

Offset

1,2

Comments

Invented by the HR concept formation program.

Links

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

S. Colton, Refactorable Numbers - A Machine Invention, J. Integer Sequences, Vol. 2, 1999, #2.

S. Colton, HR - Automatic Theory Formation in Pure Mathematics

Example

14 has 4 divisors and 4 is a digit in the base 10 representation of 14.

Mathematica

Select[Range[300], MemberQ[IntegerDigits[#], DivisorSigma[0, #]]&] (* Harvey P. Dale, Sep 02 2013 *)

Prog

(Haskell)
a036433 n = a036433_list !! (n-1)
a036433_list = filter f [1..] where
   f x = d < 10 && ("0123456789" !! d) `elem` show x where d = a000005 x
-- Reinhard Zumkeller, Mar 15 2012
(Python)
from sympy import divisor_count
A036433_list = []
for i in range(1, 10**5):
....d = divisor_count(i)
....if d < 10 and str(d) in str(i):
........A036433_list.append(i) # Chai Wah Wu, Jan 07 2015

Crossrefs

Cf. A045708, A208272.

Cf. A000005.

Sequence in context: A328217 A116639 A220274 * A172048 A226334 A109255

Adjacent sequences: A036430 A036431 A036432 * A036434 A036435 A036436

Keyword

base,nice,nonn

Author

Simon Colton (simonco(AT)cs.york.ac.uk)

Status

approved