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.

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A146091 a(n) = 3*A146085(n) - 2.

Original entry on oeis.org

1, 10, 19, 82, 91, 100, 163, 172, 181, 730, 739, 748, 811, 820, 829, 892, 901, 910, 1459, 1468, 1477, 1540, 1549, 1558, 1621, 1630, 1639, 6562, 6571, 6580, 6643, 6652, 6661, 6724, 6733, 6742, 7291, 7300, 7309, 7372, 7381, 7390, 7453, 7462, 7471, 8020, 8029, 8038, 8101, 8110, 8119
Offset: 1

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Author

Vladimir Shevelev, Oct 27 2008

Keywords

Comments

Positive integers such that for every integer m==4 (mod 9) there exists a unique representation of m as a sum of the form a(l)+3a(s).

Crossrefs

Cf. A146085, A146087, A145812, A145818.

Programs

  • PARI
    isa(n) = {my(d=Vecrev(digits(n, 3)), k=3); while (k <= #d, if (d[k], return (0)); k += 2;); d[1] == 1;} \\ A146085
isok(n) = !((n+2) % 3) && isa((n+2)/3); \\ Michel Marcus, Dec 09 2018

Extensions

More terms from Michel Marcus, Dec 09 2018
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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