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.

Showing 1-4 of 4 results.

A025627 Numbers of form 6^i*8^j, with i, j >= 0.

Original entry on oeis.org

1, 6, 8, 36, 48, 64, 216, 288, 384, 512, 1296, 1728, 2304, 3072, 4096, 7776, 10368, 13824, 18432, 24576, 32768, 46656, 62208, 82944, 110592, 147456, 196608, 262144, 279936, 373248, 497664, 663552, 884736, 1179648, 1572864, 1679616, 2097152
Offset: 1

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Crossrefs

Subsequence of A025610.

Programs

  • Mathematica
    n = 10^6; Flatten[Table[6^i*8^j, {i, 0, Log[6, n]}, {j, 0, Log[8, n/6^i]}]] // Sort (* Amiram Eldar, Sep 26 2020 *)

Formula

Sum_{n>=1} 1/a(n) = (6*8)/((6-1)*(8-1)) = 48/35. - Amiram Eldar, Sep 26 2020
a(n) ~ exp(sqrt(2*log(6)*log(8)*n)) / sqrt(48). - Vaclav Kotesovec, Sep 26 2020
a(n) = 6^A025661(n) * 8^A025674(n). - R. J. Mathar, Jul 06 2025

A025650 Exponent of 5 (value of j) in n-th number of form 4^i*5^j.

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 7, 1, 2, 3, 4, 5, 6, 0, 7, 1, 8, 2, 3, 4, 5, 6, 0, 7, 1, 8, 2, 9, 3, 4, 5, 6, 0, 7, 1, 8, 2, 9, 3, 10, 4, 5, 6, 0, 7, 1, 8, 2, 9, 3, 10, 4, 11, 5, 6, 0, 7, 1, 8, 2, 9, 3, 10, 4, 11, 5, 12, 6, 0, 7, 1, 8, 2, 9
Offset: 1

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Crossrefs

Differs from A025674 at a(1881).

Programs

  • Mathematica
    With[{max = 10^10}, IntegerExponent[Sort[Flatten[Table[4^i*5^j, {i, 0, Log[4, max]}, {j, 0, Log[5, max/4^i]}]]], 5]] (* Amiram Eldar, Jul 09 2025 *)

Formula

a(n) = A112765(A025617(n)). - Amiram Eldar, Jul 09 2025

A025661 Exponent of 6 (value of i) in n-th number of form 6^i*8^j.

Original entry on oeis.org

0, 1, 0, 2, 1, 0, 3, 2, 1, 0, 4, 3, 2, 1, 0, 5, 4, 3, 2, 1, 0, 6, 5, 4, 3, 2, 1, 0, 7, 6, 5, 4, 3, 2, 1, 8, 0, 7, 6, 5, 4, 3, 2, 9, 1, 8, 0, 7, 6, 5, 4, 3, 10, 2, 9, 1, 8, 0, 7, 6, 5, 4, 11, 3, 10, 2, 9, 1, 8, 0, 7, 6, 5, 12, 4, 11, 3, 10, 2, 9, 1, 8, 0, 7, 6, 13, 5, 12, 4, 11, 3, 10, 2, 9, 1, 8, 0, 7, 14, 6, 13
Offset: 1

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Crossrefs

Differs from A025646 at a(1881).

Programs

  • Mathematica
    With[{max = 10^12}, IntegerExponent[Sort[Flatten[Table[6^i*8^j, {i, 0, Log[6, max]}, {j, 0, Log[8, max/6^i]}]]], 6]] (* Amiram Eldar, Jul 09 2025 *)

Formula

a(n) = A122841(A025627(n)). - Amiram Eldar, Jul 09 2025

A025717 Index of 6^n within sequence of numbers of form 6^i*8^j.

Original entry on oeis.org

1, 2, 4, 7, 11, 16, 22, 29, 36, 44, 53, 63, 74, 86, 99, 112, 126, 141, 157, 174, 192, 211, 230, 250, 271, 293, 316, 340, 365, 390, 416, 443, 471, 500, 530, 561, 593, 625, 658, 692, 727, 763, 800, 838, 876, 915, 955, 996, 1038, 1081, 1125, 1169, 1214, 1260, 1307, 1355
Offset: 1

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Author

Keywords

Comments

Positions of zeros in A025674. - R. J. Mathar, Jul 06 2025

Crossrefs

Differs from A025702 at a(65).
Showing 1-4 of 4 results.