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.

A259935 Infinite sequence of positive integers such that a(n) = A000005(a(1) + a(2) + ... + a(n)) for all n >= 1.

Original entry on oeis.org

2, 4, 6, 6, 4, 8, 4, 8, 4, 8, 4, 4, 8, 8, 12, 4, 8, 4, 8, 4, 3, 4, 4, 15, 8, 10, 4, 8, 8, 8, 4, 16, 4, 8, 8, 6, 6, 8, 4, 16, 4, 8, 12, 4, 4, 8, 4, 16, 12, 4, 8, 4, 8, 8, 16, 4, 8, 8, 8, 8, 8, 8, 4, 16, 4, 8, 12, 8, 16, 12, 8, 16, 12, 4, 4, 8, 8, 8, 8, 8, 24, 8, 12, 8, 4, 8, 8, 8, 16, 8, 6, 6, 8, 4, 8, 4, 8, 8, 12, 8, 18, 8, 32, 24, 18, 4, 8, 16, 4, 16, 4, 8, 12, 8, 8, 8, 8, 8, 8, 12
Offset: 1

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Author

Max Alekseyev, Jul 09 2015

Keywords

Comments

V. S. Guba (2015) proved that such an infinite sequence exists. Numerical evidence suggests that it may also be unique (cf. A259934).
If there are infinitely many n with a(n) = a(n+1), then A175304 is infinite (see comment in A259934). - Vladimir Shevelev, Jul 21 2015

Crossrefs

First differences of A259934.

Formula

a(n) = A000005(A259934(n)) = A259934(n) - A259934(n-1).
gcd(a(n), A259934(n)) = A286540(n) = A009191(A259934(n)). - Antti Karttunen, Nov 26 2017

A260084 Infinite sequence starting with a(0)=0 such that A(a(k)) = a(k-1) for all k>=1, where A(n) = n - A037445(n).

Original entry on oeis.org

0, 2, 6, 10, 14, 18, 22, 30, 34, 42, 46, 54, 58, 62, 70, 78, 82, 90, 94, 102, 106, 114, 118, 122, 130, 138, 142, 146, 154, 158, 162, 166, 174, 182, 190, 194, 210, 214, 222, 230, 238, 242, 250, 254, 270, 274, 278, 286, 294, 298, 302, 310, 314, 330, 334, 342, 346, 354, 358, 366, 374, 390, 394, 402, 410, 418, 426, 434, 442
Offset: 0

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Author

Vladimir Shevelev, Jul 15 2015

Keywords

Comments

The first infinitary analog (see also A260124) of A259934 (see comment there). Using Guba's method (2015) one can prove that such an infinite sequence exists.
All the first differences are powers of 2 (A260085). The infinitary case is interesting because here we have at least two analogs of sequences A259934, A259935 (respectively A260084, A260124 and A260085, A260123).
It is a corollary of the fact that all terms of A037445, except for n=1, are even (powers of 2). Therefore, in the analogs of A259934 we can begin with not only 0,2 (as in this sequence), but also with 0,1 (as in A260124). Then this sequence contains only the even terms, while A260124 - only the odd ones.
A generalization. For an even m, the multiplication of A260124 by 2^m and 2^(m+1) gives two infinite solutions of the system of equations for integer x_n, n>=1: A037445(x_1 + ... + x_n) = x_n/2^A005187(m), n>=1. In particular, for m=0, we obtain A260124 and A260084.

Crossrefs

Formula

a(n) = 2 * A260124(n).

A260085 Infinite sequence of positive integers such that a(n) = A037445(a(1)+a(2)+...+a(n)) for all n>=1.

Original entry on oeis.org

2, 4, 4, 4, 4, 4, 8, 4, 8, 4, 8, 4, 4, 8, 8, 4, 8, 4, 8, 4, 8, 4, 4, 8, 8, 4, 4, 8, 4, 4, 4, 8, 8, 8, 4, 16, 4, 8, 8, 8, 4, 8, 4, 16, 4, 4, 8, 8, 4, 4, 8, 4, 16, 4, 8, 4, 8, 4, 8, 8, 16, 4, 8, 8, 8, 8, 8, 8, 4, 16, 4, 8, 4, 8, 8, 16, 4, 8, 4, 8, 4, 4, 8, 8, 4, 4, 8, 4, 16, 8, 8, 4, 16, 4, 8, 8, 8, 4, 8, 4, 16, 4, 4, 16
Offset: 1

Views

Author

Vladimir Shevelev, Jul 15 2015

Keywords

Comments

The first infinitary analog (see also A260123) of A259935 (see comment there). Using Guba's method (2015) one can prove that such an infinite sequence exists.
All terms are powers of 2.

Crossrefs

Formula

a(n) = 2 * A260123(n).

A260124 The second infinite sequence starting with a(0)=0 such that A(a(k)) = a(k-1) for all k>=1, where A(n) = n - A037445(n) (cf. A260084).

Original entry on oeis.org

0, 1, 3, 5, 7, 9, 11, 15, 17, 21, 23, 27, 29, 31, 35, 39, 41, 45, 47, 51, 53, 57, 59, 61, 65, 69, 71, 73, 77, 79, 81, 83, 87, 91, 95, 97, 105, 107, 111, 115, 119, 121, 125, 127, 135, 137, 139, 143, 147, 149, 151, 155, 157, 165, 167, 171, 173, 177, 179, 183, 187, 195, 197, 201, 205, 209, 213, 217, 221, 223, 231, 233, 237, 239, 243, 247, 255, 257, 261, 263, 267, 269, 271, 275, 279, 281, 283, 287, 289, 297, 301, 305
Offset: 0

Views

Author

Vladimir Shevelev, Jul 17 2015

Keywords

Comments

The second infinitary analog (after A260084) of A259934 (see comment there). Using Guba's method (2015) one can prove that such an infinite sequence exists.
All the first differences are powers of 2 (A260123).
See also comment in A260084.

Crossrefs

Formula

a(n) = A260084(n)/2.
Showing 1-4 of 4 results.