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.

A050267 Primes or negative values of primes in the sequence b(n) = 47*n^2 - 1701*n + 10181, n >= 0.

Original entry on oeis.org

10181, 8527, 6967, 5501, 4129, 2851, 1667, 577, -419, -1321, -2129, -2843, -3463, -3989, -4421, -4759, -5003, -5153, -5209, -5171, -5039, -4813, -4493, -4079, -3571, -2969, -2273, -1483, -599, 379, 1451, 2617, 3877, 5231, 6679, 8221, 9857, 11587, 13411, 15329, 17341, 19447, 21647, 31387
Offset: 1

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Author

Keywords

Comments

Terms are listed in the order of their appearance in sequence b.
This is a transformed version of the polynomial P(x) = 47*x^2 + 9*x - 5209 whose absolute value gives 43 distinct primes for -24 <= x <= 18, found by G. W. Fung in 1988. - Hugo Pfoertner, Dec 13 2019

References

  • R. K. Guy, Unsolved Problems in Number Theory, 3rd ed., Springer, 2004 (ISBN 0-387-20860-7); see Section A17, p. 59.
  • Paulo Ribenboim, The Little Book of Bigger Primes, Second Edition, Springer-Verlag New York, 2004. See p. 147.

Crossrefs

Programs

Extensions

Edited by N. J. A. Sloane, May 10 2007
Further edited by Klaus Brockhaus, Mar 20 2010
More terms (to distinguish from quadratic) from Charles R Greathouse IV, Jun 18 2017

A027726 Numbers k such that k^2+k+9 is a palindrome.

Original entry on oeis.org

0, 1, 9, 11, 13, 22, 30, 31, 138, 300, 304, 305, 331, 438, 969, 1141, 1413, 2367, 3000, 3144, 3881, 9854, 30000, 30605, 72062, 106801, 114141, 125206, 128348, 300000, 315165, 963304, 980560, 989154, 2378507, 3000000, 3040604, 3045679, 3152290, 3932806
Offset: 1

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Crossrefs

Programs

  • Mathematica
    palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 9; Select[Range[0, 3*10^5], palQ@ f@ # &]

Extensions

More terms from Giovanni Resta, Aug 29 2018

A027727 Palindromes of form k^2 + k + 9.

Original entry on oeis.org

9, 11, 99, 141, 191, 515, 939, 1001, 19191, 90309, 92729, 93339, 109901, 192291, 939939, 1303031, 1997991, 5605065, 9003009, 9887889, 15066051, 97111179, 900030009, 936696639, 5193003915, 11406560411, 13028282031, 15676667651, 16473337461, 90000300009
Offset: 1

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Comments

Palindromes h such that 4*h - 35 is a square. - Bruno Berselli, Aug 29 2018

Crossrefs

Programs

  • Mathematica
    palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 9; Select[f@ Range[0, 10^5], palQ] (* Giovanni Resta, Aug 29 2018 *)
    Select[Table[k^2+k+9,{k,0,300000}],PalindromeQ] (* Harvey P. Dale, Nov 21 2024 *)

Extensions

More terms from Giovanni Resta, Aug 29 2018

A128878 Primes of the form 47*n^2 - 1701*n + 10181.

Original entry on oeis.org

10181, 8527, 6967, 5501, 4129, 2851, 1667, 577, 379, 1451, 2617, 3877, 5231, 6679, 8221, 9857, 11587, 13411, 15329, 17341, 19447, 21647, 31387, 34057, 36821, 39679, 45677, 48817, 52051, 65927, 81307, 89561, 102647, 107197, 116579, 126337, 131357
Offset: 1

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Author

Douglas Winston (douglas.winston(AT)srupc.com), Apr 17 2007

Keywords

Comments

Primes are given in the order in which they arise for increasing n.
Polynomial generates 22 primes for 0 <= n <= 42, i.e., for n = 0, 1, 2, 3, 4, 5, 6, 7, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42.
If the definition is replaced by "Numbers n of the form 47*k^2 - 1701*k + 10181 such that either n or -n is a prime" we get (essentially) A050267.

Examples

			47k^2 - 1701k + 10181 = 21647 for k = 42.
		

References

  • R. K. Guy, Unsolved Problems in Number Theory, 3rd edition, Springer, 2004, ISBN 0-387-20860-7, Section A17, page 59.

Crossrefs

Programs

  • Mathematica
    Select[Table[47*n^2 - 1701*n + 10181, {n, 0, 100}], # > 0 && PrimeQ[#] &] (* T. D. Noe, Aug 02 2011 *)

Extensions

Edited by Klaus Brockhaus, Apr 22 2007 and by N. J. A. Sloane, May 05 2007 and May 06 2007
Showing 1-4 of 4 results.