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 1-2 of 2 results.

A067894 Write 0, 1, ..., n in binary and add as if they were decimal numbers.

Original entry on oeis.org

0, 1, 11, 22, 122, 223, 333, 444, 1444, 2445, 3455, 4466, 5566, 6667, 7777, 8888, 18888, 28889, 38899, 48910, 59010, 69111, 79221, 89332, 100332, 111333, 122343, 133354, 144454, 155555, 166665, 177776, 277776, 377777, 477787, 577798, 677898, 777999, 878109
Offset: 0

Views

Author

N. J. A. Sloane, based on a suggestion of Anne Donovan (anned3005(AT)aol.com) May 15 2003

Keywords

Comments

a(n) == floor((n+1)/2) (mod 10). - Robert G. Wilson v, May 15 2003

Examples

			a(6) = 0 + 1 + 10 + 11 + 100 + 101 + 110 = 333.
		

Crossrefs

Cf. A067895.
Partial sums of A007088.

Programs

  • Maple
    for n from 0 to 50 do s := 0: for j from 0 to n do s := s+convert(j, binary): od: printf(`%d,`,s): od:
  • Mathematica
    f[n_] := Apply[Plus, Table[ FromDigits[ IntegerDigits[i, 2]], {i, 0, n}]]; Table[ f[n], {n, 0, 36}]
    Accumulate[Table[FromDigits[IntegerDigits[n,2]],{n,0,40}]] (* Harvey P. Dale, Dec 30 2015 *)

Extensions

More terms from Robert G. Wilson v, Ray Chandler and James Sellers, May 15 2003

A122613 Integers 1 through n written in primorial base, summed as if decimal.

Original entry on oeis.org

1, 11, 22, 42, 163, 264, 374, 485, 605, 726, 926, 1127, 1337, 1548, 1768, 1989, 2289, 2590, 2900, 3211, 3531, 3852, 4252, 4653, 5063, 5474, 5894, 6315, 7315, 8316, 9326, 10337, 11357, 12378, 13478, 14579, 15689, 16800, 17920, 19041, 20241, 21442
Offset: 1

Views

Author

Jonathan Vos Post, Sep 20 2006

Keywords

Comments

cf. A049345 n written in primorial base [Places reading from right have values (1, 2, 6, 30, 210, ...) = primorials]. Primes in this sequence are a(2) = 11, a(6) = 163, a(33) = 10337.

Examples

			a(1) = A049345(1) = 1.
a(2) = A049345(1) + A049345(2) = 1 + 10 = 11.
a(3) = A049345(1) + A049345(2) + A049345(3) = 1 + 10 + 11 = 22.
a(4) = 1 + 10 + 11 + 20 = 42.
a(5) = 1 + 10 + 11 + 20 + 21 = 63.
a(6) = 1 + 10 + 11 + 20 + 21 + 100 = 163.
a(33) = 1 + 10 + 11 + 20 + 21 + 100 + 101 + 110 + 111 + 120 + 121 + 200 + 201 + 210 + 211 + 220 + 221 + 300 + 301 + 310 + 311 + 320 + 321 + 400 + 401 + 410 + 411 + 420 + 421 + 1000 + 1001 + 1010 + 1011 = 10337.
		

Crossrefs

Showing 1-2 of 2 results.