A057531 Numbers whose sum of digits and number of divisors are equal.

1, 2, 11, 22, 36, 84, 101, 152, 156, 170, 202, 208, 225, 228, 288, 301, 372, 396, 441, 444, 468, 516, 525, 530, 602, 684, 710, 732, 804, 828, 882, 952, 972, 1003, 1016, 1034, 1070, 1072, 1106, 1111, 1164, 1236, 1304, 1308, 1425, 1472, 1476, 1521, 1524

Offset

1,2

Comments

[A007953(n)/A000005(n) = c] AND [A000005(n)/A007953(n) = c], c an integer. - Ctibor O. Zizka, Jun 26 2009

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 210 terms from Daniel Arribas)

Code Golf StackExchange, Find the nth number where the digit sum equals the number of factors, coding challenge started Nov 28 2022.

Example

36 is a term as the sum of the digits of 36 is 3+6 = 9 and the number of divisors is 9 too.

Mathematica

Select[ Range[ 1000 ], DivisorSigma[ 0, # ]==Plus@@IntegerDigits[ # ]& ] (* Harvey P. Dale, Feb 19 2004 *)

Prog

See the Code Golf link.

Crossrefs

Cf. A000005, A007953, A057532, A050689, A070274, A070275, A063737, A067077.

Sequence in context: A076206 A018563 A018590 * A018661 A259298 A018711

Adjacent sequences: A057528 A057529 A057530 * A057532 A057533 A057534

Keyword

nonn,easy,base

Author

Asher Auel, Sep 03 2000

Status

approved