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A235127 Greatest k such that 4^k divides n. 6
0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,16

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

FORMULA

a(n) = valuation(n,4).

G.f.: Sum_{k>=1} x^(4^k)/(1 - x^(4^k)). - Ilya Gutkovskiy, Jan 28 2017

a(n) = A004526(A007814(n)). - Antti Karttunen, Nov 18 2017

EXAMPLE

Since 4^2 divides 32 and 4^3 does not, we have a(32) = 2. Likewise, since no positive power of 4 divides 9, a(9) = 0.

MATHEMATICA

IntegerExponent[Range@ 105, 4] (* Michael De Vlieger, Nov 18 2017 *)

PROG

(PARI) A235127(n) = valuation(n, 4); \\ Antti Karttunen, Nov 18 2017

(Sage)

n=100 #change n for more terms

[valuation(i, 4) for i in [1..n]]

CROSSREFS

Cf. A004526, A007814, A007949, A122841, A115362, A234957, A244413.

Sequence in context: A129251 A276077 A276935 * A258059 A093956 A160383

Adjacent sequences:  A235124 A235125 A235126 * A235128 A235129 A235130

KEYWORD

nonn,easy

AUTHOR

Tom Edgar, Jan 03 2014

EXTENSIONS

More terms from Antti Karttunen, Nov 18 2017

STATUS

approved

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Last modified October 15 00:14 EDT 2019. Contains 328025 sequences. (Running on oeis4.)