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

Author

Asher Auel, Sep 03 2000

Keywords

• nonn
• easy
• base

Comments

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

Examples

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

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.

Crossrefs

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

Programs

Mathematica

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