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 1-7 of 7 results.

A239502 (Round(q^prime(n)) - 1)/prime(n), where q is the tribonacci constant (A058265).

Original entry on oeis.org

4, 10, 74, 212, 1856, 5618, 53114, 1630932, 5161442, 167427844, 1729192432, 5577731626, 58401766802, 2005139696964, 69737304018266, 228184540445268, 8043367476888770, 86866463049858250, 285815985033409648, 10225367934387562098, 111384745483589787826
Offset: 3

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For n>=3, round(q^prime(n)) == 1 (mod 2*prime(n)). Proof in Shevelev link. In particular, all terms are even.

Examples

			For n=3, q^5 = 21.049..., so a(3) = (21 - 1)/5 = 4.
		

Crossrefs

A239544 (Round(c^prime(n)) - 1)/prime(n), where c is the tetranacci constant (A086088).

Original entry on oeis.org

14, 124, 390, 4118, 13690, 156122, 6351030, 22074820, 948652694, 11818395344, 41868809842, 528803858638, 24052859078262, 1108257471317098, 3982717894786008, 185987895674303758, 2422894681885464596, 8755616404517667662, 414985190213435939298
Offset: 4

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For n>=4, round(c^prime(n)) == 1 (mod 2*prime(n)). Proof in Shevelev link. In particular, all terms are even.

Crossrefs

A239564 a(n) = (round(c^prime(n)) - 1)/prime(n), where c is the pentanacci constant (A103814).

Original entry on oeis.org

154, 504, 5758, 19912, 245714, 11251030, 40679232, 1967728552, 26525975822, 97753187576, 1335948880418, 68398141417510, 3547322151373882, 13260715720748120, 697034813138756392, 9825603574709578482, 36935066391752894480, 1970457739485406707872
Offset: 5

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For n>=5, round(c^prime(n)) == 1 (mod 2*prime(n)). Proof in Shevelev link. In particular, all terms are even.

Crossrefs

A239565 (Round(c^prime(n)) - 1)/prime(n), where c is the hexanacci constant (A118427).

Original entry on oeis.org

6702, 23594, 301738, 14576792, 53653610, 2738173594, 38254296398, 143514673148, 2032676550562, 109797468019174, 6007838407290514, 22863415355711030, 1267938526864061370, 18523200405015238420, 70884650213591098558, 3989789924439684599434
Offset: 7

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For n>=7, round(c^prime(n)) == 1 (mod 2*prime(n)). Proof in Shevelev link. In particular, all terms are even.

Crossrefs

A239566 (Round(c^prime(n)) - 1)/prime(n), where c is the heptanacci constant (A118428).

Original entry on oeis.org

7200, 25562, 332466, 16472758, 61145666, 3200477798, 45473543628, 172043098818, 2478186385762, 137291966046470, 7704742900338106, 29569459376703894, 1681851263230158754, 24987922624169214866, 96433670513455876108, 5566902760779797458210
Offset: 7

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For n>=7, round(c^prime(n)) == 1 (mod 2*prime(n)). Proof in Shevelev link. In particular, all terms are even.

Crossrefs

Formula

All roots of the equation x^7-x^6-x^5-x^4-x^3-x^2-x-1 = 0
are the following: c=1.9919641966050350211,
-0.78418701799584451319 +/- 0.36004972226381653409*i,
-0.24065633852269642508 + /- 0.84919699909267892575*i,
0.52886125821602342773 +/- 0.76534196109589443115*i.
Absolute values of all roots, except for septanacci constant c, are less than 1.
Conjecture. Absolute values of all roots of the equation x^n - x^(n-1) - ... -x - 1 = 0, except for n-bonacci constant c_n, are less than 1. If the conjecture is valid, then for sufficiently large k=k(n), for all m>=k, we have round(c_n^prime(m)) == 1 (mod 2*prime(m)) (cf. Shevelev link).

A238901 a(n) is the smallest k, 1<=k<=(p_n-3)/2, such that sum{i=1,...,p_n-2k-1} 2^(i-1) Binomial(k-1+i, k)/p_n is prime; a(n)=0, if such k does not exist.

Original entry on oeis.org

1, 1, 1, 6, 2, 5, 10, 1, 3, 11, 8, 13, 21, 5, 8, 29, 19, 19, 37, 0, 11, 11, 45, 42, 25, 11, 41, 7, 62, 39, 55, 70, 29, 60, 49, 24, 1, 0, 47, 73, 49, 78, 52, 11, 80, 80, 28, 32, 0, 92, 117, 112, 43, 102, 19, 97, 47, 38, 140, 51, 152, 44, 43, 141
Offset: 4

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Vladimir Shevelev, Mar 06 2014

Keywords

Comments

Cf. comment in A238693.

Crossrefs

Extensions

More terms from Peter J. C. Moses, Mar 06 2014

A239640 a(n) is the smallest number such that for n-bonacci constant c_n satisfies round(c_n^prime(m)) == 1 (mod 2*p_m) for every m>=a(n).

Original entry on oeis.org

3, 3, 4, 5, 7, 7, 10, 13, 14, 14, 19, 23, 23, 31, 34, 34, 46, 50, 60, 65, 73, 79, 88, 92, 107, 113, 126, 139, 149, 168, 182, 198, 210, 227, 244, 265, 276, 292, 317, 340, 369, 384, 408, 436, 444, 480, 516, 540, 565, 606, 628, 669, 704, 735, 759, 810, 829, 895, 925
Offset: 2

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The n-bonacci constant is a unique root x_1>1 of the equation x^n-x^(n-1)-...-x-1=0. So, for n=2 we have Fibonacci constant phi or golden ratio (A001622); for n=3 we have tribonacci constant (A058265); for n=4 we have tetranacci constant (A086088), for n=5 (A103814), for n=6 (A118427), etc.

Examples

			Let n=2, then c_2 = phi (Fibonacci constant). We have round(c_2^2)=3 is not == 1 (mod 4), round(c_2^3)=4 is not == 1 (mod 6), while round(c_2^5)=11 == 1 (mod 10) and one can prove that for p>=5, we have round(c_2^p) == 1 (mod 2*p). Since 5=prime(3), then a(2)=3.
		

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Showing 1-7 of 7 results.