A063735 Square deficient numbers.

1, 4, 9, 16, 25, 49, 64, 81, 121, 169, 225, 256, 289, 361, 441, 484, 529, 625, 676, 729, 841, 961, 1024, 1089, 1156, 1225, 1369, 1444, 1521, 1681, 1849, 2025, 2116, 2209, 2401, 2601, 2809, 3025, 3249, 3364, 3481, 3721, 3844, 3969, 4096, 4225, 4489, 4761

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n=1..1000

Mathematica

Select[#^2 & /@ Range[70], DivisorSigma[1, #] < 2 # &]

Prog

(PARI) j=[]; for(n=1, 8000, if(sigma(n)<(2*n), a=n; if(issquare(a), j=concat(j, a)))); j
(PARI) { n=0; for (m=1, 10^9, if (issquare(m) && sigma(m)<(2*m), write("b063735.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 29 2009
(PARI) { n=0; for (m=1, 10^9, s=m^2; if (sigma(s)<(2*s), write("b063735.txt", n++, " ", s); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 29 2009]

Crossrefs

Intersection of A000290 and A005100.

Sequence in context: A279456 A069560 A075494 * A056798 A036454 A115648

Adjacent sequences: A063732 A063733 A063734 * A063736 A063737 A063738

Keyword

nonn

Author

Jason Earls, Aug 13 2001

Status

approved