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.
Luke Zieroth has authored 3 sequences.
Select[Flatten@ Array[FromDigits /@ Tuples[{1, 3, 7, 9}, #] &, 3], CompositeQ] (* Michael De Vlieger, Jun 01 2017 *)
FoldList[10 #1 + Prime@ #2 &, 0, Range@ 17] (* Michael De Vlieger, May 24 2017 *)
a(n) = fromdigits(primes(n)); \\ Kevin Ryde, Jun 22 2022
from sympy import prime
l = [0]
for i in range(20):
l += [10 * l[i] + prime(i + 1)]
print(l) # Indranil Ghosh, May 25 2017
The numbers formed by cyclic permutations of 134 are 341 and 413. The factors of 134 are 2 and 67, the factors of 341 are 11 and 31, and the factors of 413 are 7 and 59. Since these numbers are all composite and none share any common factors with each other, 134 is included on the list.
ok[n_] := Catch@ Block[{t = FromDigits /@ (RotateLeft[IntegerDigits[n], #] & /@ Range[ IntegerLength@ n])}, If[! AllTrue[t, CompositeQ], Throw@False]; Do[ If[ GCD[t[[i]], t[[j]]] > 1, Throw@False], {i, Length@t}, {j, i-1}]; True]; Select[ Range@ 1200, ok] (* Giovanni Resta, May 25 2017 *)
is(n) = {my(d=digits(n), v=vector(#d)); v[1]=n; if(isprime(n)||n==10, return(0)); for(i=2, #d, v[i] = v[i-1]\10; v[i] = v[i]+(v[i-1]-v[i]*10)*10^(#d-1); if(isprime(v[i]), return(0)); for(j=1,i-1,if(gcd(v[j], v[i])>1, return(0)))); n>1} \\ David A. Corneth, May 25 2017
from gmpy2 import is_prime, gcd, mpz A287198_list, n = [], 2 while n <= 10**6: s = str(n) if not is_prime(n) and '0' not in s: k = n for i in range(len(s)-1): s = s[1:]+s[0] m = mpz(s) if is_prime(m) or gcd(k,m) > 1: break k *= m else: A287198_list.append(n) n += 1 # Chai Wah Wu, May 27 2017
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