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A216440 a(n) = smallest m such that 2n-1 | 2^m+1, or 0 if no such m exists. 1
1, 1, 2, 0, 3, 5, 6, 0, 4, 9, 0, 0, 10, 9, 14, 0, 5, 0, 18, 0, 10, 7, 0, 0, 0, 0, 26, 0, 9, 29, 30, 0, 6, 33, 0, 0, 0, 0, 0, 0, 27, 41, 0, 0, 0, 0, 0, 0, 24, 15, 50, 0, 0, 53, 18, 0, 14, 0, 0, 0, 55, 0, 50, 0, 7, 65, 0, 0, 34, 69, 0, 0, 14, 0, 74, 0, 0, 0, 26, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

V. Raman, Table of n, a(n) for n = 1..100.

PROG

(PARI) for(i=0, 200, i++; m=0; for(x=1, i, if(((2^x+1))%i==0, m=x; break)); print1(m", ")) \\ V. Raman, Nov 22 2012

CROSSREFS

Cf. A002326.

Sequence in context: A285310 A262946 A343932 * A094720 A334495 A155800

Adjacent sequences:  A216437 A216438 A216439 * A216441 A216442 A216443

KEYWORD

nonn

AUTHOR

V. Raman, Sep 07 2012

STATUS

approved

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Last modified July 24 06:56 EDT 2021. Contains 346273 sequences. (Running on oeis4.)