The “comma sequence” starts with 1 and is defined by the property that if k and k′ are consecutive terms, the two-digit number formed from the last digit of k and the first digit of k′ is equal to the difference k′−k. If there is more than one such k′, choose the smallest, but if there is no such k′ the sequence terminates. The sequence begins 1, 12, 35, 94, 135, . . ., and, surprisingly, ends at term 2137453, which is 99999945. The paper analyzes the sequence and its generalizations to other starting values and other bases. A slight change in the rules allows infinitely long comma sequences to exist.

The comma sequence: a simple sequence with bizarre properties

Resta G.;
2024

Abstract

The “comma sequence” starts with 1 and is defined by the property that if k and k′ are consecutive terms, the two-digit number formed from the last digit of k and the first digit of k′ is equal to the difference k′−k. If there is more than one such k′, choose the smallest, but if there is no such k′ the sequence terminates. The sequence begins 1, 12, 35, 94, 135, . . ., and, surprisingly, ends at term 2137453, which is 99999945. The paper analyzes the sequence and its generalizations to other starting values and other bases. A slight change in the rules allows infinitely long comma sequences to exist.
2024
Istituto di informatica e telematica - IIT
integer sequence
File in questo prodotto:
File Dimensione Formato  
2401.14346v2.pdf

accesso aperto

Tipologia: Documento in Pre-print
Licenza: Creative commons
Dimensione 276.81 kB
Formato Adobe PDF
276.81 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/536516
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact