cp's OEIS Frontend

A092122 Let R_{k}(m) = the digit reversal of m in base k (R_{k}(m) is written in base 10). Sequence gives numbers m such that m = Sum_{d|m, d>1} R_{d}(m).

%I A092122 #12 Nov 15 2022 01:21:40
%S A092122 6,154,310,370,2829,3526,15320,20462,1164789,4336106,5782196,145582972
%N A092122 Let R_{k}(m) = the digit reversal of m in base k (R_{k}(m) is written in base 10). Sequence gives numbers m such that m = Sum_{d|m, d>1} R_{d}(m).
%e A092122 m = 154 is a term: Sum_{d|154, d>1} R_{d}(154) = 89 + 10 + 34 + 11 + 7 + 2 + 1 = 154.
%o A092122 (Python)
%o A092122 from sympy import divisors
%o A092122 from sympy.ntheory import digits
%o A092122 def fd(d, b): return sum(di*b**i for i, di in enumerate(d[::-1]))
%o A092122 def R(k, n): return fd(digits(n, k)[1:][::-1], k)
%o A092122 def ok(n):
%o A092122     s = 0
%o A092122     for d in divisors(n, generator=True):
%o A092122         if d == 1: continue
%o A092122         s += R(d, n)
%o A092122         if s > n: return False
%o A092122     return n == s
%o A092122 print([k for k in range(1, 21000) if ok(k)]) # _Michael S. Branicky_, Nov 14 2022
%Y A092122 Cf. A004086, A030101-A030108, A056960-A056963.
%K A092122 nonn,base,more
%O A092122 1,1
%A A092122 _Naohiro Nomoto_, Mar 30 2004
%E A092122 a(9)-a(12) from _Michael S. Branicky_, Nov 14 2022