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

Author

Pieter Post, Apr 01 2020

Keywords

• nonn
• base

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.

Examples

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

Crossrefs

Cf. A005188, A007770, A023052.

Programs

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**7):
    for t in range(2,21):
        if i==moda(i,t):
            print (i)
            break

Extensions

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