OFFSET
1,1
COMMENTS
Somu et al. (2023) proved that there exist infinitely many strings of consecutive Zumkeller numbers of arbitrary length. This result implies that there are infinitely many Zumkeller numbers q such that q+2 is also a Zumkeller number.
LINKS
Farid Jokar, On the differences between Zumkeller and K-layered numbers, arXiv:1902.02168 [math.NT], 2019.
Yuejian Peng and K. P. S. Bhaskara Rao, On Zumkeller numbers, Journal of Number Theory, 133(4), 2013, 1135-1155.
Sai Teja Somu, Andrzej Kukla, and Duc Van Khanh Tran, Some results on Zumkeller numbers, arXiv:2310.14149 [math.NT], 2023.
EXAMPLE
28 and 40 are in the sequence because 30 and 42 are also Zumkeller numbers.
CROSSREFS
KEYWORD
nonn
AUTHOR
Duc Van Khanh Tran, Dec 06 2023
STATUS
approved