A006094
Products of 2 successive primes.
Original entry on oeis.org
6, 15, 35, 77, 143, 221, 323, 437, 667, 899, 1147, 1517, 1763, 2021, 2491, 3127, 3599, 4087, 4757, 5183, 5767, 6557, 7387, 8633, 9797, 10403, 11021, 11663, 12317, 14351, 16637, 17947, 19043, 20711, 22499, 23707, 25591, 27221, 28891, 30967, 32399, 34571, 36863
Offset: 1
- H. E. Huntley, The Divine Proportion, A Study in Mathematical Beauty. New York: Dover, 1970. See Chapter 13, Spira Mirabilis, especially Fig. 13-5, page 173.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
- Michael S. Branicky, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe)
- A. Bernoff and R. Pennington, Problems Drive 1984, Archimedeans Problems Drive, Eureka, 45 (1985), 22-25, 50. (Annotated scanned copy)
- C. Cobeli and A. Zaharescu, A game with divisors and absolute differences of exponents, Journal of Difference Equations and Applications, Vol. 20, #11 (2014) pp. 1489-1501, DOI: 10.1080/10236198.2014.940337. Also available as arXiv:1411.1334 [math.NT], 2014.
Subset of the squarefree semiprimes,
A006881.
-
a006094 n = a006094_list !! (n-1)
a006094_list = zipWith (*) a000040_list a065091_list
-- Reinhard Zumkeller, Mar 13 2011
-
a006094_list = pr a000040_list
where pr (n:m:tail) = n*m : pr (m:tail)
pr _ = []
-- Jean-François Antoniotti, Jan 08 2020
-
[NthPrime(n)*NthPrime(n+1): n in [1..41]]; // Bruno Berselli, Feb 24 2011
-
a:= n-> (p-> p(n)*p(n+1))(ithprime):
seq(a(n), n=1..43); # Alois P. Heinz, Jan 02 2021
-
Table[ Prime[n] Prime[n + 1], {n, 40}] (* Robert G. Wilson v, Jan 22 2004 *)
Times@@@Partition[Prime[Range[60]], 2, 1] (* Harvey P. Dale, Oct 15 2011 *)
-
ithprime(i)*ithprime(i+1) $ i = 1..41 // Zerinvary Lajos, Feb 26 2007
-
g(n) = for(x=1,n,print1(prime(x)*prime(x+1)",")) \\ Cino Hilliard, Jul 28 2006
-
is(n)=my(p=precprime(sqrtint(n))); p>1 && n%p==0 && isprime(n/p) && nextprime(p+1)==n/p \\ Charles R Greathouse IV, Jun 04 2014
-
from sympy import prime, primerange
def aupton(nn):
alst, prevp = [], 2
for p in primerange(3, prime(nn+1)+1): alst.append(prevp*p); prevp = p
return alst
print(aupton(43)) # Michael S. Branicky, Jun 15 2021
-
from sympy import prime, nextprime
def A006094(n): return (p:=prime(n))*nextprime(p) # Chai Wah Wu, Oct 18 2024
A046301
Product of 3 successive primes.
Original entry on oeis.org
30, 105, 385, 1001, 2431, 4199, 7429, 12673, 20677, 33263, 47027, 65231, 82861, 107113, 146969, 190747, 241133, 290177, 347261, 409457, 478661, 583573, 716539, 871933, 1009091, 1113121, 1201289, 1317919, 1564259, 1879981, 2279269, 2494633, 2837407, 3127361, 3532343
Offset: 1
From _K. D. Bajpai_, Aug 27 2014: (Start)
a(2) = 105 is in the sequence because 105 = 3* 5 * 7, product of three successive primes.
a(3) = 385 is in the sequence because 385 = 5 * 7 * 11, product of three successive primes.
(End)
-
a046301 n = a046301_list !! (n-1)
a046301_list = zipWith3 (((*) .) . (*))
a000040_list (tail a000040_list) (drop 2 a000040_list)
-- Reinhard Zumkeller, May 12 2015
-
[NthPrime(n)*NthPrime(n+1)*NthPrime(n+2): n in [1..31]]; /* Or: */ [&*[ NthPrime(n+k): k in [0..2] ]: n in [1..31] ]; // Bruno Berselli, Feb 25 2011
-
A046301:=n->ithprime(n)*ithprime(n+1)*ithprime(n+2): seq(A028560(n), n=1..100); # K. D. Bajpai, Aug 27 2014
-
Table[Prime[n] Prime[n+1] Prime[n+2],{n,50}] (* K. D. Bajpai, Aug 27 2014 *)
Times@@@Partition[Prime[Range[40]],3,1] (* Harvey P. Dale, Mar 25 2019 *)
-
a(n)=prime(n)*prime(n+1)*prime(n+2); \\ Joerg Arndt, Aug 30 2014
A046303
Product of 5 successive primes.
Original entry on oeis.org
2310, 15015, 85085, 323323, 1062347, 2800733, 6678671, 14535931, 31367009, 58642669, 95041567, 162490421, 259106347, 385499687, 600662303, 907383479, 1249792339, 1673450759, 2276990377, 3024658859, 4132280413, 5717264681
Offset: 1
-
[&*[ NthPrime(n+k): k in [0..4] ]: n in [1..22]]; // Bruno Berselli, Feb 25 2011
-
lst={};Do[p0=Prime[n];p1=Prime[n+1];p2=Prime[n+2];p3=Prime[n+3];p4=Prime[n+4];a=p0*p1*p2*p3*p4;AppendTo[lst,a],{n,5!}];lst (* Vladimir Joseph Stephan Orlovsky, Mar 10 2009 *)
Times@@@Partition[Prime[Range[200]],5,1] (* Harvey P. Dale, Oct 21 2011 *)
-
first(n)=my(P=primes(n+4)); vector(n,i,prod(j=i,i+4,P[j])) \\ Charles R Greathouse IV, Jun 27 2019
A046324
Product of 6 successive primes.
Original entry on oeis.org
30030, 255255, 1616615, 7436429, 30808063, 86822723, 247110827, 595973171, 1348781387, 2756205443, 5037203051, 9586934839, 15805487167, 25828479029, 42647023513, 66238993967, 98733594781, 138896412997, 202652143553
Offset: 1
-
[&*[ NthPrime(n+k): k in [0..5] ]: n in [1..19] ]; // Bruno Berselli, Feb 25 2011
-
Times@@@Partition[Prime[Range[200]],6,1] (* Harvey P. Dale, Oct 21 2011 *)
A046326
Product of 8 successive primes.
Original entry on oeis.org
9699690, 111546435, 1078282205, 6685349671, 35336848261, 131710070791, 435656388001, 1204461778591, 3359814435017, 8618654420261, 18128893780549, 39181802686993, 75186702453419, 133869006807307, 245945384599471
Offset: 1
-
[&*[ NthPrime(n+k): k in [0..7] ]: n in [1..15]]; // Bruno Berselli, Feb 25 2011
-
Times@@@Partition[Prime[Range[50]],8,1] (* Harvey P. Dale, Oct 21 2011 *)
A046327
Numbers that are the product of 9 successive primes.
Original entry on oeis.org
223092870, 3234846615, 33426748355, 247357937827, 1448810778701, 5663533044013, 20475850236047, 63836474265323, 198229051666003, 525737919635921, 1214635883296783, 2781907990776503, 5488629279099587
Offset: 1
-
[&*[ NthPrime(n+k): k in [0..8] ]: n in [1..13]]; // Bruno Berselli, Feb 25 2011
-
Table[Product[Prime[x+n], {n, 0, 8}], {x, 100}] (* Vladimir Joseph Stephan Orlovsky, Aug 26 2008 *)
Times@@@Partition[Prime[Range[25]],9,1] (* Harvey P. Dale, Mar 05 2011 and Zak Seidov, Feb 09 2012 *)
-
a(n)=prod(k=0,8,prime(n+k))
A046325
Product of 7 successive primes.
Original entry on oeis.org
510510, 4849845, 37182145, 215656441, 955049953, 3212440751, 10131543907, 25626846353, 63392725189, 146078888479, 297194980009, 584803025179, 1058967640189, 1833822011059, 3113232716449, 5232880523393, 8194888366823
Offset: 1
-
[&*[ NthPrime(n+k): k in [0..6] ]: n in [1..17]]; // Bruno Berselli, Feb 25 2011
-
Times@@@Partition[Prime[Range[50]],7,1] (* Harvey P. Dale, Oct 21 2011 *)
A097889
Numbers that are products of (at least two) consecutive primes.
Original entry on oeis.org
6, 15, 30, 35, 77, 105, 143, 210, 221, 323, 385, 437, 667, 899, 1001, 1147, 1155, 1517, 1763, 2021, 2310, 2431, 2491, 3127, 3599, 4087, 4199, 4757, 5005, 5183, 5767, 6557, 7387, 7429, 8633, 9797, 10403, 11021, 11663, 12317, 12673, 14351, 15015, 16637, 17017
Offset: 1
Bart la Bastide (bart(AT)xs4all.nl), Sep 21 2004
-
import Data.Set (singleton, deleteFindMin, insert)
a097889 n = a097889_list !! (n-1)
a097889_list = f $ singleton (6, 2, 3) where
f s = y : f (insert (w, p, q') $ insert (w `div` p, a151800 p, q') s')
where w = y * q'; q' = a151800 q
((y, p, q), s') = deleteFindMin s
-- Reinhard Zumkeller, May 12 2015, Aug 26 2011
-
isA097889 := proc(n)
local plist,p,i ;
plist := sort(convert(numtheory[factorset](n),list)) ;
if nops(plist) < 2 then
return false;
end if;
for i from 1 to nops(plist) do
p := op(i,plist) ;
if modp(n,p^2) = 0 then
return false;
end if;
if i > 1 then
if nextprime(op(i-1,plist)) <> p then
return false;
end if;
end if;
end do:
true;
end proc:
for n from 1 to 1000 do
if isA097889(n) then
printf("%d,",n);
end if;
end do: # R. J. Mathar, Jan 12 2016
-
a = {}; Do[ AppendTo[a, Apply[ Times, (Prime /@ Partition[ Range[30], n, i]), 1]], {n, 2, 6}, {i, n - 1}]; Take[ Union[ Flatten[ a]], 45] (* Robert G. Wilson v, Sep 24 2004 *)
-
list(lim)=my(v=List(), p, t); for(e=2, log(lim+.5)\log(2), p=1; t=prod(i=1, e-1, prime(i)); forprime(q=prime(e), lim, t*=q/p; if(t>lim, next(2)); listput(v, t); p=nextprime(p+1))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Oct 24 2012
-
import heapq
from sympy import sieve
sieve.extend(10**6)
primes = list(sieve._list)
def prime(n): return primes[n-1]
def aupton(terms, verbose=False):
p = prime(1)*prime(2); h = [(p, 1, 2)]; nextcount = 3; alst = []
while len(alst) < terms:
(v, s, l) = heapq.heappop(h)
alst.append(v)
if verbose: print(f"{v}, [= Prod_{{i = {s}..{l}}} prime(i)]")
if v >= p:
p *= prime(nextcount)
heapq.heappush(h, (p, 1, nextcount))
nextcount += 1
v //= prime(s); s += 1; l += 1; v *= prime(l)
heapq.heappush(h, (v, s, l))
return alst
print(aupton(45)) # Michael S. Branicky, Jun 15 2021
A255483
Infinite square array read by antidiagonals downwards: T(0,m) = prime(m), m >= 1; for n >= 1, T(n,m) = T(n-1,m)*T(n-1,m+1)/gcd(T(n-1,m), T(n-1,m+1))^2, m >= 1.
Original entry on oeis.org
2, 3, 6, 5, 15, 10, 7, 35, 21, 210, 11, 77, 55, 1155, 22, 13, 143, 91, 5005, 39, 858, 17, 221, 187, 17017, 85, 3315, 1870, 19, 323, 247, 46189, 133, 11305, 5187, 9699690, 23, 437, 391, 96577, 253, 33649, 21505, 111546435, 46
Offset: 0
The top left corner of the array, row index 0..5, column index 1..10:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29
6, 15, 35, 77, 143, 221, 323, 437, 667, 899
10, 21, 55, 91, 187, 247, 391, 551, 713, 1073
210, 1155, 5005, 17017, 46189, 96577, 215441, 392863, 765049, 1363783
22, 39, 85, 133, 253, 377, 527, 703, 943, 1247
858, 3315, 11305, 33649, 95381, 198679, 370481, 662929, 1175921, 1816879
- Alois P. Heinz, Antidiagonals n = 0..125, flattened
- C. Cobeli, A. Zaharescu, A game with divisors and absolute differences of exponents, Journal of Difference Equations and Applications, Vol. 20, #11, 2014.
- C. Cobeli, A. Zaharescu, A game with divisors and absolute differences of exponents, arXiv:1411.1334 [math.NT], 2014.
- Discussion of SeqFan-mailing list
- Index entries for sequences related to Gilbreath conjecture and transform
A kind of generalization of
A036262.
-
T:= proc(n, m) option remember; `if`(n=0, ithprime(m),
T(n-1, m)*T(n-1, m+1)/igcd(T(n-1, m), T(n-1, m+1))^2)
end:
seq(seq(T(n, 1+d-n), n=0..d), d=0..10); # Alois P. Heinz, Feb 28 2015
-
T[n_, m_] := T[n, m] = If[n == 0, Prime[m], T[n-1, m]*T[n-1, m+1]/GCD[T[n-1, m], T[n-1, m+1]]^2]; Table[Table[T[n, 1+d-n], {n, 0, d}], {d, 0, 10}] // Flatten (* Jean-François Alcover, Mar 09 2015, after Alois P. Heinz *)
-
T=matrix(N=15,N);for(j=1,N,T[1,j]=prime(j));(f(x,y)=x*y/gcd(x,y)^2);for(k=1,N-1,for(j=1,N-k,T[k+1,j]=f(T[k,j],T[k,j+1])));A255483=concat(vector(N,i,vector(i,j,T[j,1+i-j]))) \\ M. F. Hasler, Sep 17 2016
-
A255483(n,k)=prod(j=0,n,if(bitand(n-j,j),1,prime(j+k))) \\ M. F. Hasler, Sep 18 2016
-
(define (A255483 n) (A255483bi (A002262 n) (+ 1 (A025581 n))))
;; Then use either an almost standalone version (requiring only A000040):
(define (A255483bi row col) (if (zero? row) (A000040 col) (let ((a (A255483bi (- row 1) col)) (b (A255483bi (- row 1) (+ col 1)))) (/ (lcm a b) (gcd a b)))))
;; Or one based on M. F. Hasler's new recurrence:
(define (A255483bi row col) (if (= 1 col) (A123098 row) (A003961 (A255483bi row (- col 1)))))
;; Antti Karttunen, Sep 18 2016
Original entry on oeis.org
31, 71, 167, 311, 1151, 3119, 4871, 5711, 6791, 14831, 24071, 33911, 60167, 79031, 101159, 106367, 115631, 158231, 235751, 259751, 366791, 402551, 455471, 565919, 635711, 644951, 1124831, 1347971, 1510799, 1547927, 1743419, 1851671, 2048471
Offset: 1
Cf.
A127345,
A127347,
A127351,
A006094,
A002110,
A034962,
A034965,
A082246,
A082251,
A127340,
A127341,
A070934,
A046301,
A046302,
A046303,
A046324,
A046325,
A046326,
A046327.
-
b = {}; a = {}; Do[If[PrimeQ[Prime[x] Prime[x + 1] + Prime[x] Prime[x + 2] + Prime[x + 1] Prime[x + 2]], AppendTo[a, Prime[x] Prime[x + 1] + Prime[x] Prime[x + 2] + Prime[x + 1] Prime[x + 2]], AppendTo[b, Prime[x] Prime[x + 1] + Prime[x] Prime[x + 2] + Prime[x + 1] Prime[x + 2]]], {x, 1, 100}]; Print[a] (* Artur Jasinski, Jan 11 2007 *)
s[li_] := li[[1]]*(li[[2]]+li[[3]])+li[[2]]*li[[3]]; Select[(s[#]&/@Partition[Prime[Range[100]], 3, 1]), PrimeQ] (* Zak Seidov, Jan 13 2012 *)
-
{m=143;k=2;for(n=1,m,a=sum(i=n,n+k-1,sum(j=i+1,n+k,prime(i)*prime(j)));if(isprime(a),print1(a,",")))} \\ Klaus Brockhaus, Jan 21 2007
-
{m=143;k=2;for(n=1,m,a=polcoeff(prod(j=0,k,(x-prime(n+j))),1);if(isprime(a),print1(a,",")))} \\ Klaus Brockhaus, Jan 21 2007
-
p=2; q=3; forprime(r=5, 1e3, if(isprime(t=p*q+p*r+q*r), print1(t", ")); p=q; q=r) \\ Charles R Greathouse IV, Jan 13 2012
Showing 1-10 of 18 results.
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