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 1-10 of 20 results. Next

A000799 a(n) = floor(2^n / n).

Original entry on oeis.org

2, 2, 2, 4, 6, 10, 18, 32, 56, 102, 186, 341, 630, 1170, 2184, 4096, 7710, 14563, 27594, 52428, 99864, 190650, 364722, 699050, 1342177, 2581110, 4971026, 9586980, 18512790, 35791394, 69273666, 134217728, 260301048, 505290270, 981706810, 1908874353
Offset: 1

Views

Author

Keywords

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

Formula

Sum_{n>=1} 1/a(n) = A193359. - Amiram Eldar, Apr 03 2021

A082482 a(n) = floor of (2^n-1)/n.

Original entry on oeis.org

1, 1, 2, 3, 6, 10, 18, 31, 56, 102, 186, 341, 630, 1170, 2184, 4095, 7710, 14563, 27594, 52428, 99864, 190650, 364722, 699050, 1342177, 2581110, 4971026, 9586980, 18512790, 35791394, 69273666, 134217727, 260301048, 505290270, 981706810
Offset: 1

Views

Author

Jon Perry, Apr 27 2003

Keywords

Comments

a(n) is the largest exponent k such that (2^n)^k || (2^n)!. - Lekraj Beedassy, Jan 15 2024

Examples

			a(3) = floor((2^3-1)/3) = floor(7/3) = floor(2.333) = 2.
		

Crossrefs

a(n) = A053638(n) - 1.

Programs

  • Maple
    seq(floor((2^n-1)/n), n=1..100); # Robert Israel, Dec 01 2016
  • PARI
    for (n=1,50,print1(floor((2^n-1)/n)","))

Formula

a(n) = (2^n - 1 - A082495(n))/n = A162214(n)/n. - Robert Israel, Dec 01 2016

A129795 a(n) = floor(5^n/n).

Original entry on oeis.org

5, 12, 41, 156, 625, 2604, 11160, 48828, 217013, 976562, 4438920, 20345052, 93900240, 435965401, 2034505208, 9536743164, 44878791360, 211927625868, 1003867701480, 4768371582031, 22706531343005, 108372081409801
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A082493 a(n) = n*ceiling(2^n/n) - 2^n.

Original entry on oeis.org

0, 0, 1, 0, 3, 2, 5, 0, 1, 6, 9, 8, 11, 10, 7, 0, 15, 8, 17, 4, 13, 18, 21, 8, 18, 22, 1, 12, 27, 26, 29, 0, 25, 30, 17, 8, 35, 34, 31, 24, 39, 20, 41, 28, 28, 42, 45, 32, 19, 26, 43, 36, 51, 26, 12, 24, 49, 54, 57, 44, 59, 58, 55, 0, 33, 2, 65, 52, 61, 26, 69, 8, 71, 70, 7, 60, 59, 14
Offset: 1

Views

Author

Vladeta Jovovic, Apr 28 2003

Keywords

Comments

Least nonnegative k such that (2^n+k)/n is an integer.
If n is a power of 2, a(n) = 0; otherwise a(n) = n - A015910(n). - Robert Israel, Apr 08 2015

Crossrefs

Programs

Formula

a(n) = -(2^n) mod n. - Robert Israel, Apr 08 2015

A129794 a(n) = floor(4^n/n).

Original entry on oeis.org

4, 8, 21, 64, 204, 682, 2340, 8192, 29127, 104857, 381300, 1398101, 5162220, 19173961, 71582788, 268435456, 1010580540, 3817748707, 14467258260, 54975581388, 209430786243, 799644820200, 3059510616420, 11728124029610
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A129796 a(n) = floor(6^n/n).

Original entry on oeis.org

6, 18, 72, 324, 1555, 7776, 39990, 209952, 1119744, 6046617, 32981550, 181398528, 1004668770, 5597440292, 31345665638, 176319369216, 995685849690, 5642219814912, 32071565263710, 182807922003148, 1044616697160850
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A129797 a(n) = floor(7^n/n).

Original entry on oeis.org

7, 24, 114, 600, 3361, 19608, 117649, 720600, 4483734, 28247524, 179756976, 1153440600, 7453000800, 48444505203, 316504100662, 2077058160600, 13684147881600, 90467422106136, 599941851861744, 3989613314880600
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A129798 a(n) = floor(8^n/n).

Original entry on oeis.org

8, 32, 170, 1024, 6553, 43690, 299593, 2097152, 14913080, 107374182, 780903144, 5726623061, 42288908760, 314146179364, 2345624805922, 17592186044416, 132458812569720, 1000799917193443, 7585009898729256
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A129799 a(n) = floor(9^n/n).

Original entry on oeis.org

9, 40, 243, 1640, 11809, 88573, 683281, 5380840, 43046721, 348678440, 2852823600, 23535794706, 195528140640, 1634056603925, 13726075472976, 115813761803240, 981010688215680, 8338590849833284, 71097458824894320
Offset: 1

Views

Author

Mohammad K. Azarian, May 18 2007

Keywords

Crossrefs

Programs

A053639 a(n) = ceiling(2^(n+1)/n).

Original entry on oeis.org

4, 4, 6, 8, 13, 22, 37, 64, 114, 205, 373, 683, 1261, 2341, 4370, 8192, 15421, 29128, 55189, 104858, 199729, 381301, 729445, 1398102, 2684355, 5162221, 9942054, 19173962, 37025581, 71582789, 138547333, 268435456, 520602097
Offset: 1

Views

Author

N. J. A. Sloane, Mar 23 2000

Keywords

Crossrefs

Programs

Showing 1-10 of 20 results. Next