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.
Select[Range[0, 50000], If[#!! - 512 > 0, PrimeQ[#!! - 512]] &]
for(n=1, 1e4, if (ispseudoprime(m=prod(k=0, (n-1)\2, n - 2*k) - 512), print1(n", "))) \\ Altug Alkan, Nov 06 2015
A139163:=n->(ithprime(n)! + 5)/5; seq(A139163(n), n=3..15); # Wesley Ivan Hurt, Jan 23 2014
Table[(Prime[n]! + 5)/5, {n, 3, 30}]
a(n) = (prime(n)!+5)/5; \\ Michel Marcus, Jan 23 2014
f:= proc(n) local F,m,Q,E,p;
F:= ifactors(n)[2];
m:= nops(F);
Q:= map(t -> t[1],F);
E:= map(t -> t[2],F);
p:= max(Q)-1;
do
p:= nextprime(p);
if andmap(i -> add(floor(p/Q[i]^j),j=1..floor(log[Q[i]](p))) >= E[i], [$1..m]) then return p fi;
od
end proc:
f(1):= 2:
map(numtheory:-pi @ f, [$1..100]); # Robert Israel, Mar 07 2018
a = {}; Do[m = 1; While[ ! IntegerQ[Prime[m]!/n], m++ ]; AppendTo[a, m], {n, 1, 100}]; a
a(n) = forprime(p=2,, if (!(p! % n), return (primepi(p)))); \\ Michel Marcus, Mar 08 2018
f:= proc(n) local F,m,Q,E,p;
F:= ifactors(n)[2];
m:= nops(F);
Q:= map(t -> t[1],F);
E:= map(t -> t[2],F);
p:= max(Q)-1;
do
p:= nextprime(p);
if andmap(i -> add(floor(p/Q[i]^j),j=1..floor(log[Q[i]](p))) >= E[i], [$1..m]) then return p fi;
od
end proc:
f(1):= 2:
map(f, [$1..100]); # Robert Israel, Mar 07 2018
a = {}; Do[m = 1; While[ ! IntegerQ[Prime[m]!/n], m++ ]; AppendTo[a, Prime[m]], {n, 1, 100}]; a
a(n) = forprime(p=2,, if (!(p! % n), return (p))); \\ Michel Marcus, Mar 08 2018
Table[ n!! - 1, {n,0,35} ]
Table[(Prime[n]! + 6)/6, {n, 2, 30}]
Table[(Prime[n]! + 7)/7, {n, 4, 30}]
0 is in the sequence since 0!*2^0 + 1 = 2 is prime.
[n: n in [0..3*10^2] | IsPrime(Factorial(n)*2^n+1)]; // Vincenzo Librandi, Apr 05 2015
Select[Range[0, 20000], PrimeQ[2^#*#! + 1] &]
for(n=0,300,if(ispseudoprime(n!*2^n+1),print1(n,", "))) \\ Derek Orr, Apr 05 2015
from sympy import factorial, isprime
for n in range(0,300):
if isprime(factorial(n)*(2**n)+1):
print(n, end=', ') # Stefano Spezia, Dec 06 2018
Select[Range[0, 50000], #!! - 128 > 0 && PrimeQ[#!! - 128] &]
is(n)=ispseudoprime(prod(i=0,(n-1)\2, n-2*i)-128) \\ Charles R Greathouse IV, May 11 2015
use ntheory ":all"; use Math::GMPz;
sub mf2 { my($n,$P)=(shift,Math::GMPz->new(1)); $P *= $n-($_<<1) for 0..($n-1)>>1; $P; }
for (1..100000) { say if is_prob_prime(mf2($)-128) } # _Dana Jacobsen, May 13 2015
from gmpy2 import is_prime, mpz A257864_list, g, h = [], mpz(105), mpz(128) for i in range(9,10**5,2): g *= i if is_prime(g-h): A257864_list.append(i) # Chai Wah Wu, May 12 2015
19!3 - 3^10 = 19*16*13*10*7*4*1 - 59049 = 1047511 is prime, so 19 is in the sequence.
MultiFactorial[n_, k_] := If[n < 1, 1, If[n < k + 1, n, n*MultiFactorial[n - k, k]]]; Select[Range[17, 50000], PrimeQ[MultiFactorial[#, 3] - 3^10] &]
tf(n) = prod(i=0, (n-1)\3, n-3*i); for(n=1, 1e4, if(ispseudoprime(tf(n) - 3^10), print1(n , ", "))) \\ Altug Alkan, Dec 04 2015
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