

A092959


Least square of the form 'product of n successive terms of an arithmetic progression + 1', or 0 if no such square exists.


1



4, 4, 16, 25, 121, 5041, 5041, 0, 2504902401, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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OFFSET

1,1


COMMENTS

Conjecture: No term is zero.
All terms in the progression are required to be positive. Zero values are highly probable but unproved. I have checked for each a(n) up to 10^(3*n+8).  David Wasserman, Aug 11 2006


LINKS

Table of n, a(n) for n=1..24.


EXAMPLE

a(3) = 16 = 1*3*5 + 1, a(4) = 25 = 1*2*3*4 + 1.


PROG

(PARI) f(n, x, y) = prod(i = 0, n  1, x + i*y) + 1; for (n = 8, 24, LIMIT = 10^(3*n + 8); x = 1; y = 1; num = f(n, 1, 1); while (num < LIMIT, while (num < LIMIT, if (issquare(num), print([n, num])); y++; num = f(n, x, y)); x++; y = 1; num = f(n, x, y)));  David Wasserman, Aug 11 2006


CROSSREFS

Sequence in context: A156232 A053441 A065732 * A330054 A183433 A322039
Adjacent sequences: A092956 A092957 A092958 * A092960 A092961 A092962


KEYWORD

less,nonn


AUTHOR

Amarnath Murthy, Mar 25 2004


EXTENSIONS

More terms from David Wasserman, Aug 11 2006


STATUS

approved



