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

1,3

Comments

There are exactly 5 such numbers (Property 17 of Clerc).

Links

Table of n, a(n) for n=1..5.

René-Louis Clerc, Quelques nombres de Niven-Harshad particuliers, 2023.

Example

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.

Prog

(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, ", ")))

Crossrefs

Cf. A368939, A115518, A257766, A061209, A061210, A254000, A130680, A366507, A366512.

Sequence in context: A344738 A113644 A234059 * A032433 A225036 A104830

Adjacent sequences: A370247 A370248 A370249 * A370251 A370252 A370253

Keyword

nonn,base,fini,full

Author

René-Louis Clerc, Feb 13 2024

Status

approved