A339581 Indices of records in A063377.

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

Offset

1,2

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

Table of n, a(n) for n=1..10.

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.

Formula

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

Crossrefs

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

Sequence in context: A024239 A338734 A309994 * A256962 A266807 A355574

Adjacent sequences: A339578 A339579 A339580 * A339582 A339583 A339584

Keyword

nonn,more

Author

N. J. A. Sloane, Dec 24 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

Status

approved