A140866 Number of Niven numbers <= 10^n.

10, 33, 213, 1538, 11872, 95428, 806095, 6954793, 61574510, 553007106, 5024332415, 45975917532, 422675487735, 3902487368735, 36116199480944, 335270244411437, 3128167760734131, 29410615796612778, 278977554117741592, 2664295247105153610, 25539536718894979516

Offset: 1

Author

Lekraj Beedassy, Jul 20 2008

Keywords

• nonn
• base

References

• J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 213, pp 62, Ellipses, Paris 2008.

Links

• Hiroaki Yamanouchi, Table of n, a(n) for n = 1..100
• J.-M. DeKoninck and N. Doyon, On the number of Niven numbers up to x, Fib. Quart. 41 (5) (2003) 431.
• Shyam Sunder Gupta, On Some Special Numbers, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 22, 527-565.
• Hiroaki Yamanouchi, Python code

Crossrefs

Cf. A005349, A086706.

Formula

a(n) = A086706(10^n).

Extensions

a(10)-a(12) from Donovan Johnson, Mar 10 2010

a(13)-a(21) from Hiroaki Yamanouchi, Mar 08 2014