A177512 A053735-deficient numbers.

1, 2, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251

Offset

1,2

Comments

For definition, see A175522.

All primes, except for 3, are in the sequence.

It also contains squared primes p^2 for p = 5, 7, 11, 13, 19, 23, 29, 31, 37.. (not matching current OEIS sequences). What characterizes these p?

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

{n: sum_{d|n, d<n} A053735(d) < A053735(n)}.

Prog

(Sage) is_A177512 = lambda n: sum(A053735(d) for d in divisors(n)) < 2*A053735(n) # D. S. McNeil, Dec 11 2010
(PARI) isok(n) = sumdiv(n, d, (d<n)* vecsum(digits(d, 3))) < vecsum(digits(n, 3)); \\ Michel Marcus, Feb 06 2016

Crossrefs

Cf. A177511 (perfect version), A175524, A175811, A000040, A005100, A005101.

Sequence in context: A157829 A020581 A081259 * A118751 A173494 A137519

Adjacent sequences: A177509 A177510 A177511 * A177513 A177514 A177515

Keyword

nonn,base

Author

Vladimir Shevelev, Dec 11 2010

Status

approved