A256074 Squares representable as k*m + k + m, where k >= m > 1 are squares.

49, 169, 324, 441, 961, 1849, 2209, 3249, 5329, 8281, 12321, 15129, 17424, 17689, 24649, 33489, 44521, 58081, 58564, 64009, 65025, 74529, 94249, 103684, 117649, 145161, 177241, 191844, 214369, 237169, 257049, 305809, 361201, 423801, 480249, 494209, 573049, 660969, 700569

Offset

1,1

Comments

A subsequence of A254671.

The sequence of square roots of a(n) begins: 7, 13, 18, 21, 31, 43, 47, 57, 73, 91, 111, 123, 132, 133, 157, 183, 211, 241, 242, 253, 255, 273, 307, 322, 343.

Links

Table of n, a(n) for n=1..39.

Example

a(1) = 49 = 4*9 + 4 + 9.
a(2) = 169 = 9*16 + 9 + 16.

Prog

(PARI) v=[]; for(m=2, 100, for(k=m, 10^3, if(issquare(s=(k*m)^2+k^2+m^2), v=concat(v, s)))); vecsort(v) \\ Derek Orr, Mar 21 2015

Crossrefs

Cf. A000290, A066938, A254671.

Sequence in context: A074216 A216870 A254624 * A369565 A016922 A277793

Adjacent sequences: A256071 A256072 A256073 * A256075 A256076 A256077

Keyword

nonn

Author

Alex Ratushnyak, Mar 14 2015

Status

approved