A339581 Indices of records in A063377.

1, 2, 89, 1122659, 19099919, 85864769, 26089808579, 554688278429, 4090932431513069, 95405042230542329

Offset: 1

Author

N. J. A. Sloane, Dec 24 2020

Keywords

• nonn
• more

Comments

The records themselves begin 0,5,6,7,8,9,10,12,13,14.

a(11) <= 90616211958465842219 = A005602(15). Between a(10) and this upper bound could be another record which might not be listed in A005602.

a(n) == 9 mod 10 for n > 2 (see A063377). - Michael S. Branicky, Dec 24 2020

References

• Carl Pomerance, Problem 81:21 (= 321), in R. K. Guy link.

Links

• R. K. Guy, editor, Western Number Theory Problems, 1985-12-21 & 23, Typescript, Jul 13 1986, Dept. of Math. and Stat., Univ. Calgary, 11 pages. Annotated scan of pages 1, 3, 7, 9, with permission.

Crossrefs

Cf. A005602, A057331, A063377, A063378, A339579, A339580.

Formula

a(n) = A057331(n + 2) for n >= 2. - David A. Corneth, Dec 25 2020

Extensions

a(6) corrected and a(7) found by David A. Corneth, Dec 24 2020.

a(8)-a(10) were taken from A057331 and the bound on a(11) was taken from A005602. - David A. Corneth and Amiram Eldar, Dec 25 2020