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.

A358677 Irregular triangle where row n gives the columns of A340316 whose minimum value is in row n of A340316. The lists of column indices are given in abbreviated form, using pairs (x, y) to mean the range [x..y].

Original entry on oeis.org

1, 16, 18, 18, 21, 21, 17, 17, 19, 20, 22, 265549, 265604, 265605, 265608, 265681, 265683, 265829, 265831, 265831, 265835, 265836, 265850, 265850, 265853, 265853, 265862, 265873, 265550, 265603, 265606, 265607, 265682, 265682, 265830, 265830, 265832, 265834, 265837, 265849, 265851, 265852, 265854, 265861
Offset: 1

Views

Author

Michel Marcus, Dec 12 2022

Keywords

Comments

This sequence is a spin-off from old comments of A340316 (see history there).
Pending availability of tighter constraints, we assume that there are no more values in row n here only after we reach a column of A340316 where the value in A340316 row n is greater than the value in A340316 row n+2.
Presumably, using the results from Landau as they apply to A276176, it can similarly be shown that every row here is finite. - Peter Munn, Dec 20 2022

Examples

			First 2 rows are:
 {1..16, 18..18, 21..21} for [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,21];
 {17..17, 19..20, 22..265549, 265604..265605, 265608..265681, 265683..265829, 265831..265831, 265835..265836, 265850..265850, 265853..265853, 265862..265873}.
The A340316 first 2 rows being:
   1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22
  -----------------------------------------------------------------
   2  3  5  7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79
   6 10 14 15 21 22 26 33 34 35 38 39 46 51 55 57 58 62 65 69 74 77
     the first columns that give row 2:           ^^    ^^ ^^    ^^
Row 3 begins: {265550..265603, 265606..265607, 265682..265682, 265830..265830, 265832..265834, ...
		

Crossrefs

Programs

  • PARI
    showlist(list) = {my(slist = List()); listput(slist, list[1]); for (i=2, #list, if (list[i] != list[i-1]+1, listput(slist, list[i-1]); listput(slist, list[i]););); listput(slist, list[#list]); Vec(slist);}
    primo(i) = factorback(primes(i));
    ubound(nL, n) = {if (nL == 1, return(n*log(n) + n*log(log(n)))); if (nL == 2, return(n*log(n)/log(log(n)))); if (nL == 3, return(2*n*log(n)/log(log(n))^2)); if (nL == 4, return(3*n*log(n)/log(log(n))^3)); if (nL == 5, return(4*n*log(n)/log(log(n))^4));}
    out(list1, list2, list3) = print(showlist(list1)); print(showlist(list2)); print(showlist(list3));
    rows() = {my(nL = 3, nC = 1000000, nB=5); my(m=vector(nL, i, vector(nC))); my(vfirst = vector(nL, i, primo(i))); my(list1 = List(), list2 = List(), list3 = List()); for (nn=1, nB, my(ok=1); print("nn=", nn); for (i=1, nL, my(list = List()); my(na = vfirst[i]); my(ns = 1); if (nn==1, m[i][ns] = na; ns++); forsquarefree (k=na+1, 100*round(ubound(i,nn*nC)), if (omega(k[2]) == i, m[i][ns] = k[1]; ns++); if (ns > nC, break)); if (ns < nC, print("not enough"); out(list1, list2, list3); return;);); N = 1; for (j=1, nC, if (m[N][j] == vecmin (vector(nL, r, m[r][j])), listput(list1, j+(nn-1)*nC));); N = 2; for (j=1, nC, if (m[N][j] == vecmin (vector(nL, r, m[r][j])), listput(list2, j+(nn-1)*nC));); N = 3; for (j=1, nC, if (m[N][j] == vecmin (vector(nL, r, m[r][j])), listput(list3, j+(nn-1)*nC));); vfirst = vector(nL, i, m[i][nC]); for (i=1, nL, m[i] = vector(nC));); out(list1, list2, list3);}

Extensions

Provisional rule for calculating that row n is full added by Peter Munn, Jan 03 2023