Higher order derivatives of trigonometric functions, Stirling numbers of the second kind, and Zeon algebra prefix ID Neto, Antônio Francisco J. Integer Seq. 17(9), Article 14.9.3, 9 p., electronic only (2014)
A famous identity of Hajós in terms of sets prefix ID Duarte, Rui; de Oliveira, António Guedes J. Integer Seq. 17(9), Article 14.9.1, 10 p., electronic only (2014)
On the ratio of the sum of divisors and Euler's totient function. II. prefix ID Broughan, Kevin A.; Zhou, Qizhi J. Integer Seq. 17(9), Article 14.9.2, 22 p., electronic only (2014)
