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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 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: A318662 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 October 21 06:24 EDT 2018. Contains 316405 sequences. (Running on oeis4.)