A084004 Squares obtained as a concatenation of k and 10's complement of k.

64, 7921, 9604, 164836, 351649, 996004, 19758025, 20647936, 29757025, 30846916, 97990201, 99960004, 1203187969, 1975180249, 3086469136, 4265657344, 8143618564, 9999600004, 115644884356, 131504868496, 132231867769, 140039859961, 173879826121, 339900660100, 391600608400

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..65

Formula

a(n) = A084005(n)^2. - Andrew Howroyd, Sep 21 2024

Prog

(PARI) b(n)={my(k=logint(n, 10)+1); (n+1)*10^k - n}
{ for(k=1, 10^6, my(x=b(k)); if(issquare(x), print1(x, ", "))) } \\ Andrew Howroyd, Sep 22 2024

Crossrefs

Cf. A084005, A084006, A084007.

Sequence in context: A063410 A075417 A294083 * A264016 A160448 A302271

Adjacent sequences: A084001 A084002 A084003 * A084005 A084006 A084007

Keyword

base,nonn

Author

Amarnath Murthy, May 23 2003

Extensions

More terms from Ray Chandler, May 31 2003

Offset changed and a(22) onwards from Andrew Howroyd, Sep 21 2024

Status

approved