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.

A090724 Defined in Comments lines.

Original entry on oeis.org

4, 1, 3, 5, 3, 4, 1, 3, 4, 1, 3, 5, 5, 2, 0, 5, 2, 4, 1, 6, 3, 3, 0, 6, 4, 2, 3, 5, 2, 3, 1, 4, 2, 3, 3, 5, 5, 2, 0, 3, 5, 3, 1, 3, 5, 3, 1, 6, 3, 1, 0, 5, 5, 2, 0, 5, 2, 4, 3, 5, 2, 4, 2, 3, 4, 3, 1, 6, 3, 3, 3, 4, 5, 2, 2, 3, 3, 2, 0, 3, 5, 2, 3, 4, 4, 1, 3, 5, 3, 3, 0, 4, 5, 2, 0, 6, 2, 3, 2, 6, 3, 1, 2, 5, 5
Offset: 4

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Author

Roger L. Bagula, Jan 18 2004

Keywords

Comments

1. Start with the sequence of final digits of primes (A007652), beginning at 7 so that all members of this sequence will be either 1,3,7, or 9: {7,1,3,7,9,3,9,1,7,1,3,7,3,9,1,7,1,3,...}.
2. Replace all 3's with 6's, all 1's with 3's, all 7's with 5's and all 9's with 4's: {5,3,6,5,4,6,4,3,5,3,6,5,6,4,3,5,3,6, ...}.
3. Subtract (n mod 4) from the n-th member of this sequence (i.e. subtract 1 from the first, 5th, 9th, 13th, ... members, subtract 2 from the 2nd, 6th, 10th, ... members and subtract 3 from the 3rd, 7th, 11th,... members) to get the final sequence: {4,1,3,5,3,4,1,3,4,1,3,5,5,2,0,5,2,4, ...}.
The {0,1,2,3,4,5,6} symbols coded onto the modulo 4 cycle {1,2,3,4} by the prime digits set {1,3,7,9}.

Programs

  • Mathematica
    ReplaceAll[Table[Mod[Prime[n+3], 10], {n, 200}], {1->3, 3->6, 7->5, 9->4}]-Table[Mod[n, 4], {n, 200}]