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A131840 Additive persistence of Cullen numbers. 1
0, 0, 1, 2, 1, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2, 3, 2, 2, 3, 3, 2, 2, 3, 3, 2, 2, 3, 2, 3, 3, 3, 3, 2, 3, 3, 2, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 2, 3, 2, 2, 3, 2, 3, 3, 3, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 3, 2, 3, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

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

EXAMPLE

Cullen number 385 --> 3+8+5=16 -->1+6=7 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. A002064, A131837.

Sequence in context: A144159 A073610 A285797 * A179752 A085693 A067995

Adjacent sequences:  A131837 A131838 A131839 * A131841 A131842 A131843

KEYWORD

easy,nonn,base

AUTHOR

Paolo P. Lava and Giorgio Balzarotti, Jul 20 2007

EXTENSIONS

Corrected entries and Maple code by Paolo P. Lava, Dec 19 2017

STATUS

approved

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Last modified February 22 11:50 EST 2018. Contains 299452 sequences. (Running on oeis4.)