A278817 The least t such that there exists a sequence n = b_1 < b_2 < ... < b_t = A277278(n) such that b_1 + b_2 +...+ b_t is a perfect square.

1, 1, 3, 2, 1, 5, 2, 2, 6, 1, 3, 3, 2, 4, 3, 3, 1, 2, 4, 3, 3, 5, 2, 2, 2, 1, 3, 4, 4, 2, 2, 2, 3, 4, 4, 6, 1, 5, 3, 2, 2, 5, 5, 5, 3, 3, 3, 3, 2, 1, 6, 6, 3, 3, 3, 3, 6, 6, 2, 2, 2, 4, 4, 3, 1, 7, 7, 4, 4, 2, 2, 2, 3, 3, 3, 5, 5, 5, 5, 4, 2, 1, 2, 2, 2, 5, 5

Offset

0,3

Comments

a(n) = 1 if and only if n is square.

a(n) = 2 if and only if A277278(n) = A278818(n).

Links

Peter Kagey, Table of n, a(n) for n = 0..3000

Example

a(0) = 1 via 0                  = 0^2
a(1) = 1 via 1                  = 1^2
a(2) = 3 via 2 + 3 + 4          = 3^2
a(3) = 2 via 3 + 6              = 3^2
a(4) = 1 via 4                  = 2^2
a(5) = 5 via 5 + 6 + 7 + 8 + 10 = 6^2
a(6) = 2 via 6 + 10             = 4^2

Crossrefs

Cf. A066400, A277278, A278818.

Sequence in context: A077819 A030313 A300219 * A171746 A113977 A183162

Adjacent sequences: A278814 A278815 A278816 * A278818 A278819 A278820

Keyword

nonn

Author

Peter Kagey, Nov 28 2016

Status

approved