A183087 Generalized canyon primes.
101, 103, 107, 109, 307, 313, 317, 401, 409, 419, 439, 503, 509, 523, 547, 601, 607, 613, 617, 619, 647, 659, 701, 709, 719, 727, 739, 757, 769, 809, 823, 827, 829, 839, 857, 859, 907, 919, 929, 937, 947, 967, 1013, 1019, 1039, 1049, 1069, 2017, 2027, 2029
Offset: 1
Examples
Illustration of 751379 as a generalized canyon prime: . . . . . 9 . . . . . . 7 . . . 7 . . . . . . . . 5 . . . . . . . . . . . . . 3 . . . . . . . . . . 1 . . . . . . . . .
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..24356 (full sequence)
Programs
-
Python
from sympy import isprime from itertools import chain, combinations as combs ups = list(chain.from_iterable(combs(range(10), r) for r in range(2, 11))) s = set(L[::-1] + R[1:] for L in ups for R in ups if L[0] == R[0]) afull = sorted(filter(isprime, (int("".join(map(str, t))) for t in s))) print(afull[:50]) # Michael S. Branicky, Aug 04 2022
Extensions
Missing 601 inserted by Michael S. Branicky, Aug 04 2022
Comments