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.

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A026146 a(n) = (1/2)*|s(n) - s(n-1)|, where s = A026145.

Original entry on oeis.org

2, 2, 1, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2
Offset: 3

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A026144 Numbers k such that s(j) < s(k) for all j < k, where s = A026142.

Original entry on oeis.org

1, 2, 4, 6, 7, 10, 12, 13, 16, 18, 19, 21, 22, 25, 28, 30, 31, 34, 36, 37, 39, 40, 43, 46, 48, 49, 52, 54, 55, 57, 58, 61, 63, 64, 66, 67, 70, 73, 75, 76, 79, 82, 84, 85, 88, 90, 91, 93, 94, 97, 100, 102, 103, 106, 108, 109, 111, 112, 115, 117, 118, 120, 121
Offset: 1

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A026290 a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, s(1) = 1, s(n) = 4, |s(i) - s(i-1)| <= 1 for i >=2, |s(2) - s(1)| = 1, |s(3) - s(2)| = 1 if s(2) = 1. Also a(n) = T(n,n-4), where T is the array in A026268.

Original entry on oeis.org

1, 4, 14, 46, 145, 446, 1349, 4034, 11966, 35290, 103642, 303458, 886548, 2585922, 7534245, 21934524, 63826041, 185668816, 540034074, 1570719570, 4568920029, 13292253106, 38679350746, 112583530784, 327793747775, 954702193796
Offset: 4

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Pairwise sums of A026145.
Pairwise sums of A026125.

Formula

G.f.: 32z^4(1-z)(1-z^2)/[1-z+sqrt(1-2z-3z^2)]^5.
Showing 1-3 of 3 results.