A186191 First digit of tetranacci numbers A000288.

1, 1, 1, 1, 4, 7, 1, 2, 4, 9, 1, 3, 6, 1, 2, 4, 9, 1, 3, 6, 1, 2, 4, 9, 1, 3, 6, 1, 2, 4, 9, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 6, 1, 2, 4, 8, 1, 3, 5, 1, 2, 4, 8, 1, 3, 5, 1, 2, 4, 8, 1, 3, 5

Offset: 0

Author

Carmine Suriano, Feb 14 2011

Keywords

• nonn
• base

Comments

Sequence obeys Benford law about distribution of first digits in a sequence: P(n)=Log(1+1/n).

Examples

			a(9)=9 since Tetra(9)=94.
		

Links

• Index entries for sequences related to Benford's law

Crossrefs

Cf. A000288.

Programs

Mathematica

t = {1,1,1,1}; Do[AppendTo[t, t[[-1]] + t[[-2]] + t[[-3]] + t[[-4]]], {100}]; Table[IntegerDigits[i][[1]], {i, t}]
IntegerDigits[#][[1]]&/@LinearRecurrence[{1,1,1,1},{1,1,1,1},120] (* Harvey P. Dale, Nov 08 2024 *)

Extensions

Offset changed by Georg Fischer, Jun 26 2024