A370250 Numbers k such that the sum of the digits times the square of the sum of the fourth powers of the digits equals k.
0, 1, 5873656512, 7253758561, 29961747275
Offset: 1
Examples
7253758561 = (7+2+5+3+7+5+8+5+6+1)*(7^4 + 2^4 + 5^4 + 3^4 + 7^4 + 5^4 + 8^4 + 5^4 + 6^4 + 1^4)^2 = 49*148035889 = 7253758561.
Links
- René-Louis Clerc, Quelques nombres de Niven-Harshad particuliers, 2023.
Programs
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PARI
niven142(k) = my(d=digits(k)); vecsum(d)*sum(i=1, #d, d[i]^4)^2 == k; for(k=0,10^12,if(niven142(k)==1,print1(k, ", ")))
Comments