A215138 Numbers n such that n > d(n)^2/2 where d = A000005

1, 3, 5, 7, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85

Offset

1,2

Comments

n <= A000005(n)^2/2 begins: 2, 4, 6, 8, 12, 18, 24, 30, 36, 48, 60, 72, 120.

Links

Table of n, a(n) for n=1..73.

Example

a(1)=1 because 1 > A000005(1)^2/2 = 1^2/2 = 1/2;
a(2)=3 because 3 > A000005(3)^2/2 = 2^2/2 = 2;
a(3)=5 because 5 > A000005(5)^2/2 = 2^2/2 = 2;
a(4)=7 because 7 > A000005(7)^2/2 = 2^2/2 = 2;
a(5)=9 because 9 > A000005(9)^2/2 = 3^2/2 = 9/2;
a(6)=10 because 10 > A000005(1)^2/2 = 4^2/2 =8.

Prog

(PARI) is(n)=numdiv(n)^2/2<n

Crossrefs

Cf. A035033, A035035.

Sequence in context: A258432 A344000 A128938 * A367539 A093373 A096849

Adjacent sequences: A215135 A215136 A215137 * A215139 A215140 A215141

Keyword

nonn

Author

Gerasimov Sergey, Aug 04 2012

Status

approved