login
A097421
a(n) = (5^(2^n) - 1)/2^(n+2).
3
1, 3, 39, 12207, 2384185791, 181898940354585647583, 2117582368135750847670806251699104905128479, 573971850987445072250359637315549647372395291392620860111695169081258427468128502368927
OFFSET
0,2
CROSSREFS
Cf. A070632.
Sequence in context: A076628 A198411 A367033 * A180418 A166999 A319955
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Aug 21 2004
STATUS
approved