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 1-6 of 6 results.

A245709 Fixed points of A245705 and A245706.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 24, 32, 40, 43, 48, 53, 64, 80, 86, 96, 106, 128, 160, 172, 192, 212, 249, 256, 320, 344, 384, 417, 424, 498, 512, 640, 688, 768, 834, 848, 996, 1024, 1280, 1321, 1376, 1536, 1668, 1696, 1992, 2048, 2560, 2642, 2752, 3072, 3336, 3392, 3984, 4096, 5120, 5284, 5504, 5545, 6144, 6672, 6784, 6827, 7081, 7968, 8192
Offset: 1

Views

Author

Antti Karttunen, Jul 30 2014

Keywords

Comments

The odd terms less than 2^25 are: 1, 3, 5, 43, 53, 249, 417, 1321, 5545, 6827, 7081, 8535, 1485465, 1876261, 3298409, 13937375.
Contains also all such numbers k that A245608(k) = A245708(k), because that condition implies that A245607(A245708(k)) = k = A245707(A245608(k)). Conjecture: contains no numbers outside of that set, that is, for all n, A245608(a(n)) = A245708(a(n)).

Crossrefs

A000079 is a subsequence.

Programs

A245711 Permutation of natural numbers, odd bisection of A245705 incremented by one and halved: a(n) = (1+A245705((2*n)-1)) / 2.

Original entry on oeis.org

1, 2, 3, 5, 7, 4, 19, 10, 35, 9, 17, 139, 107, 6, 37, 36, 23, 13, 555, 229, 87, 22, 275, 1676, 39, 11, 27, 68, 63, 326, 137, 28, 4435, 18, 53, 147, 25, 8, 6819, 9388, 995, 16, 155, 73, 3659, 14, 533, 838, 145, 20, 49, 851, 29, 587, 535, 403, 4179, 26, 501, 1059, 1611, 1163, 69, 152, 663, 51, 283, 222, 181, 21
Offset: 1

Views

Author

Antti Karttunen, Jul 30 2014

Keywords

Crossrefs

Inverse: A245712.

Programs

Formula

a(n) = (1+A245705((2*n)-1)) / 2.

A245605 Permutation of natural numbers: a(1) = 1, a(2n) = 2 * a(A064989(2n-1)), a(2n-1) = 1 + (2 * a(A064989(2n-1)-1)).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 9, 10, 7, 8, 13, 18, 17, 26, 11, 12, 37, 34, 25, 74, 15, 16, 69, 50, 21, 14, 19, 20, 33, 138, 41, 66, 35, 52, 53, 22, 277, 82, 31, 32, 45, 554, 65, 90, 27, 36, 1109, 130, 101, 42, 43, 28, 73, 2218, 149, 30, 71, 104, 57, 146, 209, 114, 51, 148, 133, 70, 293, 418, 555, 164, 141, 586, 329, 282, 75, 68, 105, 106, 1173, 658, 23, 24
Offset: 1

Views

Author

Antti Karttunen, Jul 29 2014

Keywords

Comments

The even bisection halved gives A245607. The odd bisection incremented by one and halved gives A245707.

Crossrefs

Programs

  • PARI
    A064989(n) = my(f = factor(n)); for(i=1, #f~, if((2 == f[i,1]),f[i,1] = 1,f[i,1] = precprime(f[i,1]-1))); factorback(f);
    A245605(n) = if(1==n, 1, if(0==(n%2), 2*A245605(A064989(n-1)), 1+(2*A245605(A064989(n)-1))));
    for(n=1, 10001, write("b245605.txt", n, " ", A245605(n)));
    
  • Scheme
    ;; With memoization-macro definec.
    (definec (A245605 n) (cond ((= 1 n) 1) ((even? n) (* 2 (A245605 (A064989 (- n 1))))) (else (+ 1 (* 2 (A245605 (-1+ (A064989 n))))))))

Formula

a(1) = 1, a(2n) = 2 * a(A064989(2n-1)), a(2n-1) = 1 + (2 * a(A064989(2n-1)-1)).
a(1) = 1, a(2n) = 2 * a(A064216(n)), a(2n-1) = 1 + (2 * a(A064216(n)-1)).
As a composition of related permutations:
a(n) = A245607(A048673(n)).

A245607 Permutation of natural numbers, the even bisection of A245605 halved: a(n) = A245605(2*n)/2.

Original entry on oeis.org

1, 2, 3, 5, 4, 9, 13, 6, 17, 37, 8, 25, 7, 10, 69, 33, 26, 11, 41, 16, 277, 45, 18, 65, 21, 14, 1109, 15, 52, 73, 57, 74, 35, 209, 82, 293, 141, 34, 53, 329, 12, 1173, 31, 36, 213, 149, 104, 43, 49, 20, 145, 173, 138, 81, 581, 114, 553, 71, 90, 133, 101, 282, 19, 325, 24, 457, 165, 50, 77, 97, 62, 105, 555, 42
Offset: 1

Views

Author

Antti Karttunen, Jul 29 2014

Keywords

Crossrefs

Programs

Formula

a(n) = A245605(2*n)/2.
As a composition of related permutations:
a(n) = A245605(A064216(n)).
a(n) = A245705(A245707(n)).

A245706 Permutation of natural numbers: a(n) = A245707(A245608(n)).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 11, 8, 7, 10, 27, 12, 9, 22, 75, 16, 19, 14, 15, 20, 51, 54, 659, 24, 35, 18, 91, 44, 565, 150, 83, 32, 21, 38, 67, 28, 13, 30, 99, 40, 139, 102, 43, 108, 33, 1318, 651, 48, 73, 70, 115, 36, 53, 182, 63, 88, 105, 1130, 19179, 300, 1107, 166, 8875, 64, 555, 42
Offset: 1

Views

Author

Antti Karttunen, Jul 30 2014

Keywords

Comments

The even bisection halved gives the sequence back. The odd bisection incremented by one and halved gives A245712.

Crossrefs

Inverse: A245705.
Fixed points: A245709.

Programs

Formula

a(n) = A245707(A245608(n)).

A245708 Permutation of natural numbers, the odd bisection of A245606 incremented by one and halved: a(n) = (1+A245606((2*n)-1))/2.

Original entry on oeis.org

1, 2, 3, 5, 4, 8, 6, 11, 7, 14, 13, 41, 10, 23, 63, 20, 15, 17, 9, 50, 16, 26, 21, 65, 45, 32, 18, 44, 30, 413, 58, 95, 22, 53, 12, 29, 27, 38, 66, 221, 52, 122, 48, 77, 115, 83, 748, 179, 69, 263, 25, 365, 39, 113, 153, 176, 130, 158, 508, 1007, 247, 140, 78, 242, 97, 59, 33, 89, 72, 68, 36, 47, 49, 188, 28
Offset: 1

Views

Author

Antti Karttunen, Jul 30 2014

Keywords

Crossrefs

Programs

Formula

a(n) = (1+A245606((2*n)-1))/2.
As a composition of related permutations:
a(1) = 1, and for n > 1, a(n) = A048673(1+A245606(n-1)).
a(n) = A245608(A245705(n)).
Other identities:
For all n >= 0, a(2^n) = A245608(2^n). Moreover, A245709 gives all such k that a(k) = A245608(k).
Showing 1-6 of 6 results.