A036342
Prime concatenated analog clock numbers read clockwise.
Original entry on oeis.org
2, 3, 5, 7, 11, 23, 67, 89, 4567, 23456789, 23456789101112123, 891011121234567891011, 23456789101112123456789101112123, 567891011121234567891011121234567891011, 121234567891011121234567891011121234567891011121, 91011121234567891011121234567891011121234567891011121234567
Offset: 1
-
import heapq
from sympy import isprime
from itertools import islice
def A036342_gen(): # generator of terms
h = [(i, i) for i in range(1, 13)]
while True:
v, last = heapq.heappop(h)
if isprime(v):
yield v
nxt = 1 if last == 12 else last+1
shift = 10 if nxt < 10 else 100
heapq.heappush(h, (v*shift+nxt, nxt))
print(list(islice(A036342_gen(), 16))) # Michael S. Branicky, May 20 2024
A036344
Prime concatenated analog clock numbers (clockwise and counterclockwise).
Original entry on oeis.org
2, 3, 5, 7, 11, 23, 43, 67, 89, 109, 4567, 10987, 76543, 23456789, 6543211211, 4321121110987, 23456789101112123, 891011121234567891011, 3211211109876543211211, 23456789101112123456789101112123, 43211211109876543211211109876543, 567891011121234567891011121234567891011
Offset: 1
A373045
Prime concatenated analog clock numbers read counterclockwise. Version 2: hours > 9 may be split into individual digits.
Original entry on oeis.org
2, 3, 5, 7, 11, 19, 43, 101, 211, 1019, 1987, 2111, 21211, 76543, 101987, 432121, 4321211, 12111019, 6543212111, 9876543212111, 1019876543212111019, 654321211101987654321211, 4321211101987654321211101, 6543212111019876543212111, 76543212111019876543212111019
Offset: 1
-
A373045_row(r)={my(d=concat([digits(i)|i<-[1..12]]), p); Set([p| s<-[1..#d], d[s]&& isprime(p=fromdigits([d[(s-i)%#d+1]| i<-[1..r]]))])}\\ r-digit-terms
A373045_upto_length(L)=concat([A373045_row(r)|r<-[1..L]]) \\ M. F. Hasler, May 21 2024
-
import heapq
from sympy import isprime
from itertools import islice
def agen(): # generator of terms
digits = [1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 0, 1, 1, 1, 2]
h = [(digits[i], i) for i in range(len(digits))]
found = set()
while True:
v, last = heapq.heappop(h)
if v not in found and isprime(v):
found.add(v)
yield v
nxt = (last-1)%len(digits)
heapq.heappush(h, (v*10+digits[nxt], nxt))
print(list(islice(agen(), 25))) # Michael S. Branicky, May 20 2024
Showing 1-3 of 3 results.
Comments