A270046 Integers n such that product of first n nonzero Fibonacci numbers (A003266) is the sum of 4 but no fewer nonzero squares.

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

Author

Altug Alkan, Mar 09 2016

Keywords

• nonn

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?

Examples

			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.
		

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A003266, A004215.

Programs

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, ", ")));