A067670 Smallest prime of additive persistence n.

2, 11, 19, 199, 29998999999999999999999

Offset: 0

Author

Shyam Sunder Gupta, Feb 23 2002

Keywords

• hard
• nonn
• base

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

Examples

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

References

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

Links

• N. J. A. Sloane, The persistence of a number, J. Recreational Math., 6 (1973), 97-98.
• Eric Weisstein's World of Mathematics, Additive Persistence

Crossrefs

Cf. A003001, A045646, A006050.

Formula

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