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.

A184815 Numbers m such that prime(m) is of the form k+floor(ks/r)+floor(kt/r), where r=sqrt(2), s=sqrt(3), t=sqrt(5).

Original entry on oeis.org

2, 4, 10, 12, 13, 16, 22, 29, 30, 36, 42, 44, 45, 49, 52, 57, 59, 60, 64, 70, 71, 76, 82, 84, 90, 91, 92, 97, 101, 103, 108, 111, 114, 115, 119, 123, 125, 138, 140, 142, 149, 150, 165, 171, 178, 180, 182, 185, 189, 191, 192, 193, 195, 198, 205, 211, 215, 217, 220, 222, 224, 233, 235, 236, 247, 248, 249, 252, 254, 255, 264, 265, 269, 273, 286, 295, 301, 302, 306, 307, 309, 316, 318, 325, 326, 327, 328, 329, 332, 336
Offset: 1

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Author

Clark Kimberling, Jan 23 2011

Keywords

Comments

A184815, A184816, and A184817 partition the primes:
A184815: 3,7,29,37,... of the form n+[ns/r]+[nt/r].
A184816: 2,5,17,... of the form n+[nr/s]+[nt/s].
A184817: 11,13,19,23,31,... of the form n+[nr/t]+[ns/t].
The Mathematica code can be easily modified to print primes in the three classes.

Examples

			See A184812.
		

Crossrefs

Programs

  • Mathematica
    r=2^(1/2); s=3^(1/2); t=5^(1/2);
    a[n_]:=n+Floor [n*s/r]+Floor[n*t/r];
    b[n_]:=n+Floor [n*r/s]+Floor[n*t/s];
    c[n_]:=n+Floor[n*r/t]+Floor[n*s/t]
    Table[a[n],{n,1,120}]  (* A184812 *)
    Table[b[n],{n,1,120}]  (* A184813 *)
    Table[c[n],{n,1,120}]  (* A184814 *)
    t1={};Do[If[PrimeQ[a[n]], AppendTo[t1,a[n]]],{n,1,600}];t1;
    t2={};Do[If[PrimeQ[a[n]], AppendTo[t2,n]],{n,1,600}];t2;
    t3={};Do[If[MemberQ[t1,Prime[n]],AppendTo[t3,n]],{n,1,600}];t3
    t4={};Do[If[PrimeQ[b[n]], AppendTo[t4,b[n]]],{n,1,600}];t4;
    t5={};Do[If[PrimeQ[b[n]], AppendTo[t5,n]],{n,1,600}];t5;
    t6={};Do[If[MemberQ[t4,Prime[n]],AppendTo[t6,n]],{n,1,600}];t6
    t7={};Do[If[PrimeQ[c[n]], AppendTo[t7,c[n]]],{n,1,600}];t7;
    t8={};Do[If[PrimeQ[c[n]], AppendTo[t8,n]],{n,1,600}];t8;
    t9={};Do[If[MemberQ[t7,Prime[n]],AppendTo[t9,n]],{n,1,600}];t9
    (* Lists t3, t6, t9 match A184815, A184816, A184817. *)