A225836 Numbers of form 2^j*(4k+1), j >= 0, k >= 1.

5, 9, 10, 13, 17, 18, 20, 21, 25, 26, 29, 33, 34, 36, 37, 40, 41, 42, 45, 49, 50, 52, 53, 57, 58, 61, 65, 66, 68, 69, 72, 73, 74, 77, 80, 81, 82, 84, 85, 89, 90, 93, 97, 98, 100, 101, 104, 105, 106, 109, 113, 114, 116, 117, 121, 122, 125, 129, 130, 132, 133

Offset

1,1

Comments

A091072 without the powers of 2.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Formula

a(n) ~ 2n. - Charles R Greathouse IV, Sep 27 2015

Mathematica

mx = 149; t = {}; Do[n = 2^j (4 k + 1); If[n <= mx, AppendTo[t, n]], {j, 0, Log[2, mx]}, {k, mx/4}]; Union[t] (* T. D. Noe, May 16 2013 *)

Prog

(PARI) for(n=1, 200, t=n/2^valuation(n, 2); if(t>1&&(t%4==1), print1(n, ", ")))
(PARI) is(n)=n>>=valuation(n, 2); n%4==1 && n>1 \\ Charles R Greathouse IV, Sep 27 2015
(PARI) list(lim)=my(v=List(), t); forstep(n=5, lim, 4, listput(v, t=n); while((t<<=1)<=lim, listput(v, t))); Set(v) \\ Charles R Greathouse IV, Sep 27 2015
(Magma) [n: n in [1..200] | d gt 1 and IsOne(d mod 4) where d is n div 2^Valuation(n, 2)]; // Bruno Berselli, May 16 2013

Crossrefs

Cf. A091067.

Sequence in context: A373841 A070873 A234037 * A140509 A314580 A314581

Adjacent sequences: A225833 A225834 A225835 * A225837 A225838 A225839

Keyword

nonn,easy

Author

Ralf Stephan, May 16 2013

Status

approved