A131841 - OEIS

A131841

Additive persistence of Woodall numbers.

0, 0, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 3, 2, 3, 3, 3, 3, 2, 3, 2, 2, 2, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 2, 3, 2, 3, 2, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 2, 2, 3, 3, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 3, 2, 3, 3, 3

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OFFSET

1,5

LINKS

Table of n, a(n) for n=1..88.

EXAMPLE

Woodall number 159 --> 1+5+9=15 --> 1+5=6 thus persistence is 2

MAPLE

with(numtheory): with(combinat): P:=proc(n) local a, t; t:=0; a:=n*2^n-1; while a>9 do t:=t+1; a:=convert(convert(a, base, 10), `+`); od; t;

end: seq(P(i), i=1..10^2);

CROSSREFS

Cf. A003261, A131838.