A211890 -id:A211890 - cp's OEIS frontend

A007528 Primes of the form 6k-1.

5, 11, 17, 23, 29, 41, 47, 53, 59, 71, 83, 89, 101, 107, 113, 131, 137, 149, 167, 173, 179, 191, 197, 227, 233, 239, 251, 257, 263, 269, 281, 293, 311, 317, 347, 353, 359, 383, 389, 401, 419, 431, 443, 449, 461, 467, 479, 491, 503, 509, 521, 557, 563, 569, 587

Offset: 1

N. J. A. Sloane

For values of k see A024898.
Also primes p such that p^q - 2 is not prime where q is an odd prime. These numbers cannot be prime because the binomial p^q = (6k-1)^q expands to 6h-1 some h. Then p^q-2 = 6h-1-2 is divisible by 3 thus not prime. - Cino Hilliard, Nov 12 2008
a(n) = A211890(3,n-1) for n <= 4. - Reinhard Zumkeller, Jul 13 2012
There exists a polygonal number P_s(3) = 3s - 3 = a(n) + 1. These are the only primes p with P_s(k) = p + 1, s >= 3, k >= 3, since P_s(k) - 1 is composite for k > 3. - Ralf Steiner, May 17 2018
From Bernard Schott, Feb 14 2019: (Start)
A theorem due to Andrzej Mąkowski: every integer greater than 161 is the sum of distinct primes of the form 6k-1. Examples: 162 = 5 + 11 + 17 + 23 + 47 + 59; 163 = 17 + 23 + 29 + 41 + 53. (See Sierpiński and David Wells.)
{2,3} Union A002476 Union {this sequence} = A000040.
Except for 2 and 3, all Sophie Germain primes are of the form 6k-1.
Except for 3, all the lesser of twin primes are also of the form 6k-1.
Dirichlet's theorem on arithmetic progressions states that this sequence is infinite. (End)
For all elements of this sequence p=6*k-1, there are no (x,y) positive integers such that k=6*x*y-x+y. - Pedro Caceres, Apr 06 2019

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 870.
A. Mąkowski, Partitions into unequal primes, Bull. Acad. Polon. Sci. Sér. Sci. Math. Astr. Phys. 8 (1960), 125-126.
Wacław Sierpiński, Elementary Theory of Numbers, p. 144, Warsaw, 1964.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books, Revised edition, 1997, p. 127.

T. D. Noe, Table of n, a(n) for n = 1..1000
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
F. S. Carey, On some cases of the Solutions of the Congruence z^p^(n-1)=1, mod p, Proceedings of the London Mathematical Society, Volume s1-33, Issue 1, November 1900, Pages 294-312.
Amelia Carolina Sparavigna, The Pentagonal Numbers and their Link to an Integer Sequence which contains the Primes of Form 6n-1, Politecnico di Torino (Italy, 2021).
Amelia Carolina Sparavigna, Binary operations inspired by generalized entropies applied to figurate numbers, Politecnico di Torino (Italy, 2021).
Wikipedia, Dirichlet's theorem on arithmetic progressions.

Intersection of A016969 and A000040.
Cf. A003627, A010051, A117047, A132231, A214360, A057145.
Prime sequences A# (k,r) of the form k*n+r with 0 <= r <= k-1 (i.e., primes == r (mod k), or primes p with p mod k = r) and gcd(r,k)=1: A000040 (1,0), A065091 (2,1), A002476 (3,1), A003627 (3,2), A002144 (4,1), A002145 (4,3), A030430 (5,1), A045380 (5,2), A030431 (5,3), A030433 (5,4), A002476 (6,1), this sequence (6,5), A140444 (7,1), A045392 (7,2), A045437 (7,3), A045471 (7,4), A045458 (7,5), A045473 (7,6), A007519 (8,1), A007520 (8,3), A007521 (8,5), A007522 (8,7), A061237 (9,1), A061238 (9,2), A061239 (9,4), A061240 (9,5), A061241 (9,7), A061242 (9,8), A030430 (10,1), A030431 (10,3), A030432 (10,7), A030433 (10,9), A141849 (11,1), A090187 (11,2), A141850 (11,3), A141851 (11,4), A141852 (11,5), A141853 (11,6), A141854 (11,7), A141855 (11,8), A141856 (11,9), A141857 (11,10), A068228 (12,1), A040117 (12,5), A068229 (12,7), A068231 (12,11).
Cf. A034694 (smallest prime == 1 (mod n)).
Cf. A038700 (smallest prime == n-1 (mod n)).
Cf. A038026 (largest possible value of smallest prime == r (mod n)).
Cf. A001359 (lesser of twin primes), A005384 (Sophie Germain primes).
Cf. A048265, A324076.

Filtered(List([1..100],n->6*n-1),IsPrime); # Muniru A Asiru, May 19 2018

a007528 n = a007528_list !! (n-1)
a007528_list = [x | k <- [0..], let x = 6 * k + 5, a010051' x == 1]
-- Reinhard Zumkeller, Jul 13 2012

select(isprime,[seq(6*n-1,n=1..100)]); # Muniru A Asiru, May 19 2018

Select[6 Range[100]-1,PrimeQ]  (* Harvey P. Dale, Feb 14 2011 *)

forprime(p=2, 1e3, if(p%6==5, print1(p, ", "))) \\ Charles R Greathouse IV, Jul 15 2011

forprimestep(p=5,1000,6, print1(p", ")) \\ Charles R Greathouse IV, Mar 03 2025

A003627 \ {2}. - R. J. Mathar, Oct 28 2008
Conjecture: Product_{n >= 1} ((a(n) - 1) / (a(n) + 1)) * ((A002476(n) + 1) / (A002476(n) - 1)) = 3/4. - Dimitris Valianatos, Feb 11 2020
From Vaclav Kotesovec, May 02 2020: (Start)
Product_{k>=1} (1 - 1/a(k)^2) = 9*A175646/Pi^2 = 1/1.060548293.... =4/(3*A333240).
Product_{k>=1} (1 + 1/a(k)^2) = A334482.
Product_{k>=1} (1 - 1/a(k)^3) = A334480.
Product_{k>=1} (1 + 1/a(k)^3) = A334479. (End)
Legendre symbol (-3, a(n)) = -1 and (-3, A002476(n)) = +1, for n >= 1. For prime 3 one sets (-3, 3) = 0. - Wolfdieter Lang, Mar 03 2021

A132231 Primes congruent to 7 (mod 30).

Original entry on oeis.org

7, 37, 67, 97, 127, 157, 277, 307, 337, 367, 397, 457, 487, 547, 577, 607, 727, 757, 787, 877, 907, 937, 967, 997, 1087, 1117, 1237, 1297, 1327, 1447, 1567, 1597, 1627, 1657, 1747, 1777, 1867, 1987, 2017, 2137, 2287, 2347, 2377, 2437, 2467, 2557, 2617, 2647

Offset: 1

Omar E. Pol, Aug 15 2007

Primes ending in 7 with (SOD-1)/3 integer where SOD is sum of digits. - Ki Punches, Feb 07 2009
Intersection of A030432 and A002476. - Ray Chandler, Apr 07 2009
Only from 4927 on, there are more composite numbers than primes in {7+30k}, see A227869. - M. F. Hasler, Nov 02 2013
Terms are non-twin primes A007510, except for 7. - Jonathan Sondow, Oct 27 2017

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
C. K. Caldwell, The Prime Pages
Omar E. Pol, Prime numbers in a sieve with 30 columns
Omar E. Pol, Sobre el patrón de los números primos

Cf. A007510, A007528, A010051, A068229, A117047, A129807, A039949, A132230-A132236, A214360.

a132231 n = a132231_list !! (n-1)
a132231_list = [x | k <- [0..], let x = 30 * k + 7, a010051' x == 1]
-- Reinhard Zumkeller, Jul 13 2012

[p: p in PrimesUpTo(3000) | p mod 30 eq 7 ]; // Vincenzo Librandi, Aug 14 2012

Select[30*Range[0,100]+7,PrimeQ] (* Harvey P. Dale, Feb 01 2012 *)
Select[Prime[Range[1000]],MemberQ[{7},Mod[#,30]]&] (* Vincenzo Librandi, Aug 14 2012 *)

forstep(p=7,1999,30,isprime(p)&&print1(p",")) \\ M. F. Hasler, Nov 02 2013

a(n) = A158573(n)*30 + 7. - Ray Chandler, Apr 07 2009

a(n) = A211890(4,n-1) for n <= 5. - Reinhard Zumkeller, Jul 13 2012

Extended by Ray Chandler, Apr 07 2009

A214360 Primes congruent to 23 modulo 3120613860.

Original entry on oeis.org

23, 3120613883, 6241227743, 9361841603, 12482455463, 15603069323, 18723683183, 21844297043, 24964910903, 28085524763, 34326752483, 43688594063, 62412277223, 115462712843, 124824554423, 156030693023, 159151306883, 171633762323, 180995603903, 196598673203

Offset: 1

Reinhard Zumkeller, Jul 13 2012

nonn

A211889(9) = 3120613860;

the first 10 terms constitute row 9 of triangle A211890, an arithmetic progression of 10 primes.

Cf. A010051.

Sequences of numbers congruent 23 modulo m: A134517 m=24, A141945 m=25, A140375 m=26, A141963 m=27, A141974 m=28, A141999 m=29, A132235 m=30, A142027 m=31, A142044 m=32, A142062 m=33, A142091 m=35, A142107 m=36, A142132 m=37, A142173 m=39, A142192 m=40, A142220 m=41, A142244 m=42, A142272 m=43, A142302 m=44, A142324 m=45, A142374 m=47, A142405 m=48, A142433 m=49, A142490 m=51, A142518 m=52, A142553 m=53, A142617 m=55, A142650 m=56, A142679 m=57, A142750 m=59, A142790 m=60, A142821 m=61, A142902 m=63, A142935 m=64, A140844 m=210.

a214360 n = a214360_list !! (n-1)
a214360_list = [x | k <- [0..], let x = 3120613860*k+23, a010051' x == 1]

select(isprime,[seq(23+i*3120613860,i=0..1000)]); # Robert Israel, Jun 07 2015

Select[Range[23, 2 10^11, 3120613860], PrimeQ] (* Vincenzo Librandi, Jun 07 2015 *)

is(n)=isprime(n) && n%3120613860==23 \\ Charles R Greathouse IV, Jul 02 2016

a(n) ~ 658414080n log n. - Charles R Greathouse IV, Jul 02 2016

A117047 Primes of the form 60*n+11.

Original entry on oeis.org

11, 71, 131, 191, 251, 311, 431, 491, 911, 971, 1031, 1091, 1151, 1451, 1511, 1571, 1811, 1871, 1931, 2111, 2351, 2411, 2531, 2591, 2711, 3011, 3191, 3251, 3371, 3491, 3671, 3851, 3911, 4091, 4211, 4271, 4391, 4451, 4691, 4751, 4871, 4931, 5051, 5171

Offset: 1

Roger L. Bagula, Apr 17 2006

nonn

a(n) = A211890(5,n-1) for n <= 6. - Reinhard Zumkeller, Jul 13 2012

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Cf. A007528, A132231, A214360, A010051.

a117047 n = a117047_list !! (n-1)
a117047_list = [x | k <- [0..], let x = 60 * k + 11, a010051' x == 1]
-- Reinhard Zumkeller, Jul 13 2012

Flatten[Table[If[PrimeQ[60*n + 11], 60*n + 11, {}], {n, 0, 100}]]
Select[60Range[0,100]+11,PrimeQ] (* Harvey P. Dale, Feb 16 2024 *)

Wrong formula removed by Reinhard Zumkeller, Jul 13 2012

A211889 Smallest positive d such that prime(n)+k*d is prime for 0 <= k <= n.

Original entry on oeis.org

1, 2, 6, 30, 60, 244230, 6930, 546840, 3120613860, 7399357350, 10719893274090, 173761834256010, 14772517344885300

Offset: 1

Reinhard Zumkeller, Jul 13 2012

a(n) = A211890(n,k+1) - A211890(n,k), 0 <= k < n.

Eric Weisstein's World of Mathematics, Prime Arithmetic Progression.
Wikipedia, Primes in arithmetic progression.
Index entries for sequences related to primes in arithmetic progressions

Cf. A000040, A010051, A211890.

a211889 n = head [k | let p = a000040 n, k <- [1..],
            all ((== 1) . a010051') $ map ((+ p) . (* k)) (a002260_row n)]

from sympy import isprime, prime, primorial, primepi
def A211889(n):
    if n == 1:
        return 1
    delta = primorial(primepi(n))
    p, d = prime(n), delta
    while True:
        q = p
        for _ in range(n):
            q += d
            if not isprime(q):
                break
        else:
            return d
        d += delta # Chai Wah Wu, Jun 28 2019

A010051(A000040(n) + k * a(n)) = 1, 0 <= k <= n.

a(10) from Chai Wah Wu, Jun 29 2019

a(11)-a(13) from Giovanni Resta, Jun 30 2019

cp's OEIS Frontend

A007528 Primes of the form 6k-1.

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A132231 Primes congruent to 7 (mod 30).

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A214360 Primes congruent to 23 modulo 3120613860.

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A117047 Primes of the form 60*n+11.

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A211889 Smallest positive d such that prime(n)+k*d is prime for 0 <= k <= n.

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