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.

A262989 Predestined numbers A262743 generated from at least a pair of products in which, for each product, all digits 0 through 9 are used, and each digit appears exactly once.

Original entry on oeis.org

248665082, 248695370, 249063875, 253674980, 256175640, 257930648, 257938064, 260577504, 260817480, 263987504, 264713960, 267766632, 267953048, 269037548, 269045192, 269174192, 269307584, 269735900, 269937500
Offset: 1

Views

Author

Francesco Di Matteo, Oct 06 2015

Keywords

Comments

Sequence obtained using the A050278 sequence of pandigitals numbers "over" the A262743 sequence of predestined numbers.
Pandigital numbers are numbers containing the digits 0 through 9 (in this case Version 1: each digit appears exactly once).
This is a finite sequence: first term is 248665082 (106*2345897 and 2378*104569) and last term is 8282993378 (853*9710426 and 8503*974126).
The sequence contains 95009 terms. - Giovanni Resta, Oct 07 2015

Examples

			248665082 = 106*2345897 and 2378*104569;
248695370 = 10*24869537 and 1045*237986, 1045*237986 and 1*248695370;
249063875 = 2375*104869 and 1*249063875;
...
8270423667 = 87*95062341 and 957*8642031;
8271362484 = 957*8643012 and 8526*970134;
8282993378 = 853*9710426 and 8503*974126.
		

References

  • Francesco Di Matteo, Sequenze ludiche, Game Edizioni (2015), page 37.

Crossrefs

Programs

  • Mathematica
    good[w_]:=Block[{L={}}, Do[If[ Length[ Select[ Join[w[[i]], w[[j]]], Mod[#,10]==0&]]<=1,AppendTo[L, {w[[i]], w[[j]]}]], {i, Length@w}, {j, i-1}]; L]; f[w_]:=Select[ Table[ FromDigits/@ {Take[w, i], Take[w, i-10]}, {i, 5}], #[[1]] <= #[[2]] && IntegerLength[#[[1]]] + IntegerLength[ #[[2]]] == 10&]; p = Select[ Permutations@ Range[0, 9], First[#] > 0&]; t = SplitBy[ Sort[{ Times@@ #, #} &/@ Flatten[ f/@ p, 1]], First]; u = Select[ (Last/@ #) &/@ Select[t, Length[#] > 1&], good[#] != {} &]; seq = Union[ Times @@@ Flatten[u, 1]]; Length@ seq (* Giovanni Resta, Oct 07 2015 *)