A333670 Numbers m such that m equals abs(d_1^k - d_2^k + d_3^k - d_4^k ...), where d_i is the decimal expansion of m and k is some power greater than 2.

0, 1, 48, 240, 407, 5920, 5921, 2918379, 7444416, 18125436, 210897052, 6303187514, 8948360198, 10462450356, 11647261846, 18107015789, 27434621679, 31332052290, 4986706842391, 485927682264092, 1287253463537089, 126835771455251081, 559018292730428520, 559018292730428521

Offset

1,3

Comments

For terms > 1, the exponents k are 2, 4, 3, 4, 4, 7, 8, 8, 11, 11, 21, 11, 11, 11, 11, 13, 15, 16, 22, 21, 21.

Links

Table of n, a(n) for n=1..24.

Example

48 = abs(4^2 - 8^2), 5920 = abs(5^4 - 9^4 + 2^4 - 0^4).

Prog

(Python)
def moda(n, a)
    kk, j = 0, 1
    while n > 0:
        kk= kk-j*(n%10)**a
        n, j =int(n//10), -j
    return abs(kk)
for i in range (0, 10**12):
    for t in range(2, 21):
        if i==moda(i, t):
            print (i, t, moda(i, t))

Crossrefs

Cf. A005188, A007770, A023052.

Sequence in context: A211740 A211750 A211760 * A230136 A157913 A181773

Adjacent sequences: A333667 A333668 A333669 * A333671 A333672 A333673

Keyword

nonn,base

Author

Pieter Post, Apr 01 2020

Extensions

a(19)-a(24) from Giovanni Resta, Apr 02 2020

Status

approved