A145046 a(n) = 2*A002330(n+1) * A002331(n+1).

4, 12, 8, 20, 12, 40, 28, 60, 48, 80, 72, 20, 60, 112, 88, 140, 132, 52, 180, 168, 28, 60, 208, 120, 32, 260, 252, 160, 68, 312, 308, 288, 180, 272, 252, 340, 228, 40, 120, 420, 408, 280, 168, 380, 220, 440, 420, 532, 520, 48, 368, 240, 612, 608, 200, 572, 300, 552, 52, 260

Offset

0,1

Links

Table of n, a(n) for n=0..59.

Example

The following table shows the relationship
between several closely related sequences:
Here p = A002144 = primes == 1 mod 4, p = a^2+b^2 with a < b;
a = A002331, b = A002330, t_1 = ab/2 = A070151;
p^2 = c^2+d^2 with c < d; c = A002366, d = A002365,
t_2 = 2ab = A145046, t_3 = b^2-a^2 = A070079,
with {c,d} = {t_2, t_3}, t_4 = cd/2 = ab(b^2-a^2).
---------------------------------
.p..a..b..t_1..c...d.t_2.t_3..t_4
---------------------------------
.5..1..2...1...3...4...4...3....6
13..2..3...3...5..12..12...5...30
17..1..4...2...8..15...8..15...60
29..2..5...5..20..21..20..21..210
37..1..6...3..12..35..12..35..210
41..4..5..10...9..40..40...9..180
53..2..7...7..28..45..28..45..630
.................................

Crossrefs

4 times A070151, or (apart from initial term) twice A145019.

Cf. A070079.

Sequence in context: A372651 A361192 A310569 * A205849 A208855 A252984

Adjacent sequences: A145043 A145044 A145045 * A145047 A145048 A145049

Keyword

nonn

Author

N. J. A. Sloane, Feb 25 2009

Status

approved