A067670 Smallest prime of additive persistence n.

2, 11, 19, 199, 29998999999999999999999

Offset

0,1

Comments

a(5) >= 29*10^2222222222222222222221-1, the next number of additive persistence 5 after A006050(5). (a(5) is not equal to A006050(5) because that number is divisible by 313.) - Pontus von Brömssen, Oct 17 2023

References

H. J. Hindin, The additive persistence of a number, J. Rec. Math., 7 (No. 2, 1974), 134-135.

Links

Table of n, a(n) for n=0..4.

N. J. A. Sloane, The persistence of a number, J. Recreational Math., 6 (1973), 97-98.

Eric Weisstein's World of Mathematics, Additive Persistence

Formula

a(n) >= A006050(n). - Pontus von Brömssen, Oct 17 2023

Example

a(2) = 19, 19 -> 10 -> 1, so 2 summation steps are required to reach a single-digit number.

Crossrefs

Cf. A003001, A045646, A006050.

Sequence in context: A217308 A105076 A103200 * A217071 A159879 A017185

Adjacent sequences: A067667 A067668 A067669 * A067671 A067672 A067673

Keyword

hard,nonn,base

Author

Shyam Sunder Gupta, Feb 23 2002

Status

approved