A138121
Triangle read by rows in which row n lists the partitions of n that do not contain 1 as a part in juxtaposed reverse-lexicographical order followed by A000041(n-1) 1's.
Original entry on oeis.org
1, 2, 1, 3, 1, 1, 4, 2, 2, 1, 1, 1, 5, 3, 2, 1, 1, 1, 1, 1, 6, 3, 3, 4, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 7, 4, 3, 5, 2, 3, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 8, 4, 4, 5, 3, 6, 2, 3, 3, 2, 4, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 5, 4, 6, 3, 3, 3, 3, 7, 2, 4, 3, 2, 5, 2, 2, 3, 2, 2
Offset: 1
Triangle begins:
[1];
[2],[1];
[3],[1],[1];
[4],[2,2],[1],[1],[1];
[5],[3,2],[1],[1],[1],[1],[1];
[6],[3,3],[4,2],[2,2,2],[1],[1],[1],[1],[1],[1],[1];
[7],[4,3],[5,2],[3,2,2],[1],[1],[1],[1],[1],[1],[1],[1],[1],[1],[1];
...
The illustration of the three views of the section model of partitions (version "tree" with seven sections) shows the connection between several sequences.
---------------------------------------------------------
Partitions A194805 Table 1.0
. of 7 p(n) A194551 A135010
---------------------------------------------------------
7 15 7 7 . . . . . .
4+3 4 4 . . . 3 . .
5+2 5 5 . . . . 2 .
3+2+2 3 3 . . 2 . 2 .
6+1 11 6 1 6 . . . . . 1
3+3+1 3 1 3 . . 3 . . 1
4+2+1 4 1 4 . . . 2 . 1
2+2+2+1 2 1 2 . 2 . 2 . 1
5+1+1 7 1 5 5 . . . . 1 1
3+2+1+1 1 3 3 . . 2 . 1 1
4+1+1+1 5 4 1 4 . . . 1 1 1
2+2+1+1+1 2 1 2 . 2 . 1 1 1
3+1+1+1+1 3 1 3 3 . . 1 1 1 1
2+1+1+1+1+1 2 2 1 2 . 1 1 1 1 1
1+1+1+1+1+1+1 1 1 1 1 1 1 1 1 1
. 1 ---------------
. *<------- A000041 -------> 1 1 2 3 5 7 11
. A182712 -------> 1 0 2 1 4 3
. A182713 -------> 1 0 1 2 2
. A182714 -------> 1 0 1 1
. 1 0 1
. A141285 A182703 1 0
. A182730 A182731 1
---------------------------------------------------------
. A138137 --> 1 2 3 6 9 15..
---------------------------------------------------------
. A182746 <--- 4 . 2 1 0 1 2 . 4 ---> A182747
---------------------------------------------------------
.
. A182732 <--- 6 3 4 2 1 3 5 4 7 ---> A182733
. . . . . 1 . . . .
. . . . 2 1 . . . .
. . 3 . . 1 2 . . .
. Table 2.0 . . 2 2 1 . . 3 . Table 2.1
. . . . . 1 2 2 . .
. 1 . . . .
.
. A182982 A182742 A194803 A182983 A182743
. A182992 A182994 A194804 A182993 A182995
---------------------------------------------------------
.
From _Omar E. Pol_, Sep 03 2013: (Start)
Illustration of initial terms (n = 1..6). The table shows the six sections of the set of partitions of 6. Note that before the dissection the set of partitions was in the ordering mentioned in A026792. More generally, the six sections of the set of partitions of 6 also can be interpreted as the first six sections of the set of partitions of any integer >= 6.
Illustration of initial terms:
---------------------------------------
n j Diagram Parts
---------------------------------------
. _
1 1 |_| 1;
. _ _
2 1 |_ | 2,
2 2 |_| . 1;
. _ _ _
3 1 |_ _ | 3,
3 2 | | . 1,
3 3 |_| . . 1;
. _ _ _ _
4 1 |_ _ | 4,
4 2 |_ _|_ | 2, 2,
4 3 | | . 1,
4 4 | | . . 1,
4 5 |_| . . . 1;
. _ _ _ _ _
5 1 |_ _ _ | 5,
5 2 |_ _ _|_ | 3, 2,
5 3 | | . 1,
5 4 | | . . 1,
5 5 | | . . 1,
5 6 | | . . . 1,
5 7 |_| . . . . 1;
. _ _ _ _ _ _
6 1 |_ _ _ | 6,
6 2 |_ _ _|_ | 3, 3,
6 3 |_ _ | | 4, 2,
6 4 |_ _|_ _|_ | 2, 2, 2,
6 5 | | . 1,
6 6 | | . . 1,
6 7 | | . . 1,
6 8 | | . . . 1,
6 9 | | . . . 1,
6 10 | | . . . . 1,
6 11 |_| . . . . . 1;
...
(End)
-
less[run1_, run2_] := (lg1 = run1 // Length; lg2 = run2 // Length; lg = Max[lg1, lg2]; r1 = If[lg1 == lg, run1, PadRight[run1, lg, 0]]; r2 = If[lg2 == lg, run2, PadRight[run2, lg, 0]]; Order[r1, r2] != -1); row[n_] := Join[Array[1 &, {PartitionsP[n - 1]}], Sort[Reverse /@ Select[IntegerPartitions[n], FreeQ[#, 1] &], less]] // Flatten // Reverse; Table[row[n], {n, 1, 9}] // Flatten (* Jean-François Alcover, Jan 15 2013 *)
Table[Reverse/@Reverse@DeleteCases[Sort@PadRight[Reverse/@Cases[IntegerPartitions[n], x_ /; Last[x]!=1]], x_ /; x==0, 2]~Join~ConstantArray[{1}, PartitionsP[n - 1]], {n, 1, 9}] // Flatten (* Robert Price, May 11 2020 *)
A050268
Primes of the form 36*k^2 - 810*k + 2753, listed in order of increasing parameter k >= 0.
Original entry on oeis.org
2753, 1979, 1277, 647, 89, 359, 953, 1619, 2357, 3167, 4049, 5003, 6029, 7127, 8297, 9539, 10853, 12239, 13697, 15227, 16829, 18503, 20249, 22067, 23957, 25919, 27953, 30059, 32237, 34487, 36809, 41669, 44207, 46817, 49499, 52253
Offset: 1
- Paulo Ribenboim, The Little Book of Bigger Primes, Second Edition, Springer-Verlag New York, 2004.
-
[a: n in [0..100] | IsPrime(a) where a is 36*n^2 - 810*n + 2753]; // Vincenzo Librandi, Dec 08 2011
-
t1:=[seq(36*n^2 - 810*n + 2753,n=0..100)]; t2:=[]; for i from 1 to nops(t1) do if isprime(t1[i]) then t2:=[op(t2),t1[i]]; fi; od: t2; # N. J. A. Sloane
-
Select[Table[36n^2-810n+2753,{n,0,2000}],PrimeQ] (* Vincenzo Librandi, Dec 08 2011 *)
-
select(isprime, vector(1000, n, 36*n^2-810*n+2753)) \\ Charles R Greathouse IV, Feb 14 2011
A030341
Triangle T(n,k): write n in base 3, reverse order of digits.
Original entry on oeis.org
0, 1, 2, 0, 1, 1, 1, 2, 1, 0, 2, 1, 2, 2, 2, 0, 0, 1, 1, 0, 1, 2, 0, 1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 0, 2, 1, 1, 2, 1, 2, 2, 1, 0, 0, 2, 1, 0, 2, 2, 0, 2, 0, 1, 2, 1, 1, 2, 2, 1, 2, 0, 2, 2, 1, 2, 2, 2, 2, 2, 0, 0, 0, 1, 1, 0, 0, 1, 2, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 2, 1, 0, 1
Offset: 0
Triangle begins :
0
1
2
0, 1
1, 1
2, 1
0, 2
1, 2
2, 2
0, 0, 1
1, 0, 1
2, 0, 1
0, 1, 1
1, 1, 1
2, 1, 1 ...
-
a030341 n k = a030341_tabf !! n !! k
a030341_row n = a030341_tabf !! n
a030341_tabf = iterate succ [0] where
succ [] = [1]
succ (2:ts) = 0 : succ ts
succ (t:ts) = (t + 1) : ts
-- Reinhard Zumkeller, Feb 21 2013
-
A030341_row := n -> op(convert(n, base, 3)):
seq(A030341_row(n), n=0..32); # Peter Luschny, Nov 28 2017
-
Flatten[Table[Reverse[IntegerDigits[n,3]],{n,0,40}]] (* Harvey P. Dale, Oct 20 2014 *)
-
A030341(n, k=-1)=/*k<0&&error("Flattened sequence not yet implemented.")*/n\3^k%3 \\ Assuming that columns are numbered starting with k=0 as in A030308, A030567 and others. - M. F. Hasler, Jul 21 2013
A031298
Triangle T(n,k): write n in base 10, reverse order of digits.
Original entry on oeis.org
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 1, 1, 2, 1, 3, 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 9, 1, 0, 2, 1, 2, 2, 2, 3, 2, 4, 2, 5, 2, 6, 2, 7, 2, 8, 2, 9, 2, 0, 3, 1, 3, 2, 3, 3, 3, 4, 3, 5, 3, 6, 3, 7, 3, 8, 3, 9, 3, 0, 4, 1, 4, 2, 4, 3, 4, 4, 4, 5, 4, 6, 4, 7, 4, 8, 4, 9, 4, 0
Offset: 0
-
a031298 n k = a031298_tabf !! n !! k
a031298_row n = a031298_tabf !! n
a031298_tabf = iterate succ [0] where
succ [] = [1]
succ (9:ds) = 0 : succ ds
succ (d:ds) = (d + 1) : ds
-- Reinhard Zumkeller, Jul 04 2012
-
Table[Reverse[IntegerDigits[n]],{n,0,50}]//Flatten (* Harvey P. Dale, Mar 07 2023 *)
-
T(n,k)=n\10^(k-1)%10 \\ M. F. Hasler, Jul 21 2013
A048988
Primes of the form 4*k^2 + 4*k + 59.
Original entry on oeis.org
59, 67, 83, 107, 139, 179, 227, 283, 347, 419, 499, 587, 683, 787, 1019, 1283, 1427, 1579, 1907, 2083, 2267, 2459, 2659, 3083, 3307, 3539, 3779, 4027, 4283, 4547, 5099, 5387, 5683, 5987, 6299, 6619, 6947, 7283, 8707, 9467, 9859, 10259, 10667, 11083
Offset: 1
-
[ a: n in [0..250] | IsPrime(a) where a is 4*n^2 +4*n + 59]; // Vincenzo Librandi, Nov 19 2010
-
select(isprime, [4*k*(k+1)+59$k=0..100])[]; # Alois P. Heinz, Apr 16 2025
-
Select[(4 #^2 + 4 # + 59) & /@ Range[0, 100], PrimeQ] (* Robert Price, Apr 16 2025 *)
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lista(nn) = for(k=0, nn, if(isprime(p=4*k^2+4*k+59), print1(p, ", "))); \\ Altug Alkan, Apr 18 2018
A046563
First numerator and then denominator of each element of the 1/4-Pascal triangle (by row). To get a 1/4-Pascal triangle, replace "2" in the third row of the Pascal triangle with "1/4" and calculate all other rows as in the Pascal triangle.
Original entry on oeis.org
1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 5, 4, 5, 4, 1, 1, 1, 1, 9, 4, 5, 2, 9, 4, 1, 1, 1, 1, 13, 4, 19, 4, 19, 4, 13, 4, 1, 1, 1, 1, 17, 4, 8, 1, 19, 2, 8, 1, 17, 4, 1, 1, 1, 1, 21, 4, 49, 4, 35, 2, 35, 2, 49, 4, 21, 4, 1, 1, 1, 1, 25, 4, 35, 2, 119, 4, 35, 1, 119, 4, 35, 2, 25, 4, 1, 1, 1, 1
Offset: 1
1/1;
1/1 1/1;
1/1 1/4 1/1;
1/1 5/4 5/4 1/1;
1/1 9/4 5/2 9/4 1/1;
1/1 13/4 19/4 19/4 13/4 1/1;
1/1 17/4 8/1 19/2 8/1 17/4 1/1;
1/1 21/4 49/4 35/2 35/2 49/4 21/4 1/1; ...
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
- 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.
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
- G. W. Fung and H. C. Williams, Quadratic polynomials which have a high density of prime values, Math. Comput. 55(191) (1990), 345-353.
- Carlos Rivera, Problem 12: Prime producing polynomials, The Prime Puzzles & Problems Connection.
- Jitender Singh, Prime numbers and factorization of polynomials, arXiv:2411.18366 [math.NT], 2024.
- Eric Weisstein's World of Mathematics, Prime-Generating Polynomial.
Cf.
A002383,
A005471,
A005846,
A007635,
A022464,
A027753,
A027755,
A027758,
A048059,
A050267,
A050268,
A116206,
A117081,
A267252.
-
lst={};Do[p=47*n^2-1701*n+10181;If[PrimeQ[p],AppendTo[lst,p]],{n,0,5!}];lst (* Vladimir Joseph Stephan Orlovsky, Jan 29 2009 *)
Select[Table[47n^2-1701n+10181,{n,0,50}],PrimeQ] (* Harvey P. Dale, Oct 03 2011 *)
-
[n | n <- apply(m->47*m^2-1701*m+10181, [0..100]), isprime(abs(n))] \\ Charles R Greathouse IV, Jun 18 2017
Original entry on oeis.org
1, 1, 3, 1, 3, 1, 3, 5, 1, 5, 3, 1, 3, 5, 5, 1, 5, 3, 1, 5, 3, 5, 7, 3, 1, 3, 1, 3, 13, 3, 5, 1, 9, 1, 5, 5, 3, 5, 5, 1, 9, 1, 3, 1, 11, 11, 3, 1, 3, 5, 1, 9, 5, 5, 5, 1, 5, 3, 1, 9, 13, 3, 1, 3, 13, 5, 9, 1, 3, 5, 7, 5, 5, 3, 5, 7, 3, 7, 9, 1, 9, 1, 5, 3, 5, 7, 3, 1, 3, 11, 7, 3, 7
Offset: 1
Cf.
A046933 (number of composites between successive primes).
A271980
Numbers k such that 3*k^2 + 39*k + 37 is prime.
Original entry on oeis.org
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 25, 26, 29, 30, 31, 32, 33, 34, 35, 38, 39, 40, 41, 42, 44, 45, 46, 48, 49, 51, 52, 53, 54, 55, 57, 58, 59, 60, 63, 64, 66, 68, 69, 70, 71, 72, 79, 84, 86, 88, 89, 90, 91, 92
Offset: 1
4 is in this sequence since 3*4^2 + 39*4 + 37 = 48+156+37 = 241 is prime.
-
[n: n in [0..100] |IsPrime(3*n^2+39*n+37)]; // Vincenzo Librandi, Apr 19 2018
-
Select[Range[0, 100], PrimeQ[3*#^2 + 39*# + 37] &]
-
isok(n) = isprime(3*n^2 + 39*n + 37); \\ Michel Marcus, Apr 17 2016
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lista(nn) = for(n=0, nn, if(ispseudoprime(3*n^2+39*n+37), print1(n, ", "))); \\ Altug Alkan, Apr 18 2016
A272074
Numbers k such that k^4 + 29*k^2 + 101 is prime.
Original entry on oeis.org
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 26, 31, 32, 34, 35, 37, 43, 44, 45, 47, 49, 53, 56, 60, 61, 62, 66, 67, 68, 70, 71, 72, 74, 75, 79, 80, 81, 84, 85, 89, 90, 91, 93, 96, 99
Offset: 1
4 is in this sequence since 4^4 + 29*4^2 + 101 = 256+464+101 = 821 is prime.
-
Select[Range[0,100],PrimeQ[#^4+29#^2+101]&] (* Harvey P. Dale, Dec 15 2020 *)
-
lista(nn) = for(n=0, nn, if(ispseudoprime(n^4+29*n^2+101), print1(n, ", "))); \\ Altug Alkan, Apr 19 2016
Showing 1-10 of 3244 results.
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