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URL: https://oeis.org/A270046

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A270046
Integers n such that product of first n nonzero Fibonacci numbers (A003266) is the sum of 4 but no fewer nonzero squares.
1
6, 8, 17, 34, 35, 60, 61, 62, 67, 72, 73, 74, 88, 114, 116, 126, 128, 144, 145, 146, 165, 171, 210, 212, 223, 231, 237, 247, 257, 269, 283, 288, 289, 290, 303, 317, 324, 325, 326, 330, 332, 339, 346, 347, 354, 356, 360, 361, 362, 376, 402, 404, 415, 423, 429, 438, 440
OFFSET
1,1
COMMENTS
How is the distribution of a(n), a(n+1), a(n+2) in this sequence where a(n+2) = a(n+1) + 1 = a(n) + 2?
EXAMPLE
6 is a term because 1*1*2*3*5*8 = 240 and 240 = x^2 + y^2 + z^2 has no solution for integer values of x, y and z.
PROG
(PARI) isA004215(n) = my(fouri, j) ; fouri=1 ; while( n >=7*fouri, if( n % fouri ==0, j= n/fouri-7 ; if( j % 8==0, return(1) ) ; ); fouri *= 4 ; ) ; return(0);
a003266(n) = prod(k=1, n, fibonacci(k));
for(n=1, 1e3, if(isA004215(a003266(n)), print1(n, ", ")));
CROSSREFS
Sequence in context: A345034 A058098 A112158 * A093479 A239396 A340519
KEYWORD
nonn
AUTHOR
Altug Alkan, Mar 09 2016
STATUS
approved