A050223 Digit sums of hoax numbers A019506.

4, 13, 12, 13, 13, 10, 7, 13, 4, 9, 7, 13, 13, 11, 13, 12, 13, 13, 10, 13, 13, 13, 10, 15, 13, 15, 17, 15, 12, 13, 13, 13, 13, 15, 13, 14, 15, 11, 15, 12, 15, 15, 9, 13, 12, 15, 15, 22, 18, 14, 15, 22, 13, 15, 13, 21, 22, 22, 15, 4, 9, 14, 13, 13, 13, 13, 7, 12, 9, 17, 13

Offset: 1

Author

Eric W. Weisstein

Keywords

• nonn
• base

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Hoax Number.

Crossrefs

Cf. A007953, A019506.

Cf. A202393, A050218.

Programs

PARI

ishoax(m) = !isprime(m) && (sumdigits(m) == vecsum(apply(sumdigits, factor(m)[, 1]))); \\ A019506
lista(nn) = apply(sumdigits, select(ishoax, [1..nn])); \\ Michel Marcus, Feb 24 2023

Formula

a(n) = A007953(A019506(n)).