OFFSET
1,6
COMMENTS
Sequence obeys Benford law about distribution of first digits in a sequence P(n)=Log(1+1/n).
LINKS
EXAMPLE
a(15)=1 since Penta(15)=1921.
MATHEMATICA
t = {1, 1, 1, 1, 1}; Do[AppendTo[t, t[[-1]] + t[[-2]] + t[[-3]] + t[[-4]] + t[[-5]]], {100}]; Table[IntegerDigits[i][[1]], {i, t}]
First[IntegerDigits[#]]&/@LinearRecurrence[{1, 1, 1, 1, 1}, {1, 1, 1, 1, 1}, 110] (* Harvey P. Dale, Mar 28 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Carmine Suriano, Feb 14 2011
STATUS
approved