cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A270435 Positions of zeros in A270434; numbers n for which A270432(n) = A270433(n).

Original entry on oeis.org

96, 220, 222, 226, 272, 274, 276, 288, 376, 380, 394, 396, 398, 412, 414, 416, 422, 434, 448, 458, 462, 464, 466, 472, 476, 480, 482, 484, 486, 506, 508, 512, 514, 522, 524, 528, 590, 592, 594, 596, 618, 620, 622, 636, 638, 648, 652, 654, 656, 658, 662, 678, 680, 682, 684, 686, 688, 704, 706, 708, 992, 1008, 1016, 1024
Offset: 1

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Author

Antti Karttunen, Mar 17 2016

Keywords

Comments

Numbers n for which in the range 1 .. n there are exactly the same number of s's such that A048673(s) and A064216(s) are of the same parity than there are t's such that A048673(t) and A064216(t) are of opposite parity.
No other terms after a(2651) = 2346398 in range 1 .. 2^25.

Crossrefs

Programs

  • Mathematica
    nn = 2048; f[n_] := (Times @@ Power[If[# == 1, 1, NextPrime@ #] & /@ First@ #, Last@ #] + 1)/2 &@ Transpose@ FactorInteger@ n; g[n_] := Times @@ Power[If[# == 1, 1, NextPrime[#, -1]] & /@ First@ #, Last@ #] &@ Transpose@ FactorInteger[2 n - 1]; s = Select[Range@ nn, Xor[EvenQ@ f@ #, OddQ@ g@ #] &]; t = Select[Range@ nn, Xor[EvenQ@ f@ #, EvenQ@ g@ #] &]; Flatten@ Position[Table[Count[s, k_ /; k <= n] - Count[t, k_ /; k <= n], {n, nn/2}], n_ /; n == 0] (* Michael De Vlieger, Mar 19 2016 *)