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 1-3 of 3 results.

A055074 Pointers to base-2 digits where primes occur in A054633.

Original entry on oeis.org

3, 4, 5, 7, 8, 9, 12, 17, 19, 20, 21, 22, 29, 30, 33, 39, 47, 49, 64, 65, 71, 72, 76, 77, 83, 91, 102, 103, 106, 113, 114, 115, 120, 122, 129, 142, 155, 156, 157, 173, 174, 175, 179, 180, 185, 186, 193, 194, 197, 198, 203, 204, 225, 233, 245, 249, 264, 265, 267
Offset: 1

Views

Author

Patrick De Geest, Apr 15 2000

Keywords

Examples

			01101110010111011110001001101010111100110111101111...
--|.... sum 0+1+1 = prime 2 at position 3
---|... sum 0+1+1+0 = prime 2 at position 4
----|.. sum 0+1+1+0+1 = prime 3 at position 5
------| sum 0+1+1+0+1+1+1 = prime 5 at position 7
		

Crossrefs

A356294 a(n) = A054633(n) if A030190(n) = 1, else a(n) = a(n-A054633(n)+1).

Original entry on oeis.org

1, 2, 1, 3, 4, 5, 2, 1, 6, 3, 7, 8, 9, 4, 10, 11, 12, 13, 5, 2, 1, 14, 6, 3, 15, 16, 7, 17, 8, 18, 9, 19, 20, 21, 22, 4, 10, 23, 24, 11, 25, 26, 27, 28, 12, 29, 30, 31, 32, 33, 13, 5, 2, 1, 34, 14, 6, 3, 35, 36, 15, 16, 37, 7, 38, 17, 8, 39, 40, 41, 18, 42, 9
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 120; c =  k = 1; Do[Do[Set[b[k], #[[j]]]; If[b[k] == 1, Set[a[k], c]; c++, Set[a[k], a[k - c + 1]]]; k++, {j, Length[#]}] &@ IntegerDigits[n, 2], {n, nn}]; Array[a[#] &, k - 1] (* Michael De Vlieger, Aug 03 2022 *)

A055143 The first n digits of the juxtaposition of the base-2 numbers converted to decimal.

Original entry on oeis.org

1, 3, 6, 13, 27, 55, 110, 220, 441, 882, 1765, 3531, 7063, 14126, 28253, 56507, 113015, 226031, 452062, 904124, 1808248, 3616497, 7232994, 14465988, 28931977, 57863955, 115727910, 231455821, 462911642, 925823285, 1851646570, 3703293141, 7406586283, 14813172567
Offset: 1

Views

Author

Patrick De Geest, Apr 15 2000

Keywords

Examples

			1 (1); 11 (3); 110 (6); 1101 (13); 11011 (27); 110111 (55); ...
		

Crossrefs

Programs

  • Mathematica
    With[{c=Flatten[Table[IntegerDigits[n,2],{n,20}]]},Table[FromDigits[ Take[ c,k],2],{k,Length[c]}]] (* Harvey P. Dale, May 15 2021 *)
  • Python
    from itertools import count, islice
    def agen():
        k, chap = 1, "1"
        for n in count(1):
            while len(chap) < n: k += 1; chap += bin(k)[2:]
            yield int(chap[:n], 2)
    print(list(islice(agen(), 34))) # Michael S. Branicky, Oct 06 2022

Extensions

a(32) and beyond from Michael S. Branicky, Oct 06 2022
Showing 1-3 of 3 results.