A024782 Every suffix prime and no 0 digits in base 7 (written in base 7).

2, 3, 5, 23, 25, 32, 43, 52, 65, 443, 452, 623, 625, 632, 652, 2452, 2623, 6625, 6652, 42623, 642623, 6642623

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• easy
• base
• fini
• full

Crossrefs

Cf. A024779, A024780, A024781, A024783, A024784, A024785.

Programs

Maple

a:=[[2], [3], [5]]: b:=[]: l1:=1: l2:=3: do for k from 1 to 6 do for j from l1 to l2 do d:=[op(a[j]),k]: if(isprime(op(convert(d, base, 7, 7^nops(d)))))then a:=[op(a), d]: fi: od: od: l1:=l2+1: l2:=nops(a): if(l1>l2)then break: fi: od: seq(op(convert(a[j], base, 10, 10^nops(a[j]))), j=1..nops(a)); # Nathaniel Johnston, Jun 21 2011

Python

from sympy import isprime
def afull():
    prime_strings, alst = list("235"), []
    while len(prime_strings) > 0:
        alst.extend(sorted(int(p) for p in prime_strings))
        candidates = set(d+p for p in prime_strings for d in "123456")
        prime_strings = [c for c in candidates if isprime(int(c, 7))]
    return alst
print(afull()) # Michael S. Branicky, Apr 27 2022