A325641 - OEIS

A325641

a(1) = 1; for n > 1, a(n) = n/d for the least divisor d > 1 of n such that A048720(d,k) = n for some k.

1, 1, 1, 2, 1, 3, 1, 4, 3, 5, 1, 6, 1, 7, 5, 8, 1, 9, 1, 10, 3, 11, 1, 12, 1, 13, 9, 14, 1, 15, 1, 16, 11, 17, 5, 18, 1, 19, 13, 20, 1, 21, 1, 22, 15, 23, 1, 24, 7, 25, 17, 26, 1, 27, 1, 28, 19, 29, 1, 30, 1, 31, 21, 32, 13, 33, 1, 34, 1, 35, 1, 36, 1, 37, 25, 38, 1, 39, 1, 40, 1, 41, 1, 42, 17, 43, 1, 44, 1, 45, 1, 46, 3, 47, 19

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OFFSET

1,4

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Index entries for sequences related to polynomials in ring GF(2)[X]

FORMULA

a(n) = n / A325643(n).

PROG

(PARI) A325641(n) = if(1==n, n, my(p = Pol(binary(n))*Mod(1, 2)); fordiv(n, d, if((d>1), my(q = Pol(binary(d))*Mod(1, 2)); if(0==(p%q), return(n/d)))));

CROSSREFS

Cf. A048720, A325642, A325643.

Cf. A325559 (positions of ones after the initial 1).

Sequence in context: A366291 A353271 A326139 * A325563 A159353 A032742

Adjacent sequences: A325638 A325639 A325640 * A325642 A325643 A325644

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 11 2019

STATUS

approved