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.

Showing 1-3 of 3 results.

A095321 Primes in whose binary expansion the number of 1-bits is <= number of 0-bits minus 3.

Original entry on oeis.org

257, 521, 577, 641, 769, 1031, 1033, 1049, 1061, 1091, 1093, 1097, 1153, 1217, 1283, 1289, 1297, 1409, 1553, 1601, 2053, 2069, 2081, 2083, 2089, 2113, 2129, 2179, 2309, 2593, 2689, 3089, 3137, 3329, 4099, 4111, 4129, 4133, 4139, 4153
Offset: 1

Views

Author

Antti Karttunen, Jun 04 2004

Keywords

Crossrefs

Complement of A095320 in A000040. Subset of A095317. Cf. also A095331.

Programs

  • Maple
    filter:= proc(p) local L;
      L:= convert(p,base,2);
      2*convert(L,`+`) <= nops(L)-3
    end proc;
    select(filter, [seq(ithprime(i),i=1..1000)]); # Robert Israel, Apr 27 2025
  • Mathematica
    Select[Prime[Range[600]],DigitCount[#,2,1]<=DigitCount[#,2,0]-3&] (* Harvey P. Dale, Jul 04 2018 *)
  • PARI
    forprime(p=2, 4200, v=binary(p); s=0; for(k=1,#v, s+=if(v[k]==1,+1,-1)); if(s<=-3, print1(p,", "))) \\ Washington Bomfim, Jan 12 2011

A095330 Number of A095320-primes in range ]2^n,2^(n+1)].

Original entry on oeis.org

1, 2, 2, 5, 7, 13, 23, 42, 71, 122, 241, 412, 789, 1413, 2770, 4859, 9545, 16955, 34039, 60484, 121241, 216830, 441223, 785885, 1597803, 2867949, 5874665, 10544609, 21636090, 39034399, 80414166, 145210901, 299284792
Offset: 1

Views

Author

Antti Karttunen, Jun 04 2004

Keywords

Comments

Ratios a(n)/A036378(n) converge as: 1, 1, 1, 1, 1, 1, 1, 0.976744, 0.946667, 0.890511, 0.945098, 0.887931, 0.904817, 0.876551, 0.914191, 0.851112, 0.88799, 0.831535, 0.881041, 0.82195, 0.863934, 0.808416, 0.858898, 0.797191, 0.84356, 0.786657, 0.835979, 0.777517, 0.825576, 0.769947, 0.819026, 0.76292, 0.81036

Crossrefs

a(n) = A036378(n)-A095331(n).

A095332 Number of A095312-primes in range ]2^n,2^(n+1)].

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 4, 3, 15, 9, 47, 73, 236, 251, 863, 1180, 3298, 4284, 12933, 18598, 51300, 73371, 199410, 292156, 769127, 1131645, 2978179, 4533090, 11590386, 17623347, 44867556, 69537472
Offset: 1

Views

Author

Antti Karttunen, Jun 04 2004

Keywords

Comments

Ratios a(n)/A036378(n) converge as: 0, 0, 0, 0, 0, 0.076923, 0, 0.093023, 0.04, 0.109489, 0.035294, 0.101293, 0.083716, 0.146402, 0.082838, 0.151165, 0.109778, 0.161746, 0.110884, 0.175754, 0.132525, 0.191264, 0.142826, 0.202279, 0.154244, 0.210966, 0.161036, 0.219599, 0.172971, 0.228618, 0.179496, 0.235729, 0.188283
Ratios a(n)/A095331(n) converge as: 1, 1, 1, 1, 1, 0, 1,4, 0.75, 1, 0.642857, 0.903846, 0.879518, 1.18593, 0.965385,1.015294, 0.980066, 0.960116, 0.932115, 0.987101, 0.973972, 0.998326,1.012223, 0.997384, 0.985958, 0.988856, 0.981798, 0.987035, 0.991666, 0.993762, 0.991831, 0.994302, 0.992846

Crossrefs

a(n) = A036378(n)-A095333(n).
Showing 1-3 of 3 results.