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A063735 Square deficient numbers. +0
1
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 (list; graph; listen)
OFFSET

1,2

LINKS

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

MATHEMATICA

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

PROGRAM

(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)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), 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)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 29 2009]

CROSSREFS

Cf. A005100.

Sequence in context: A065741 A069560 A075494 this_sequence A056798 A036454 A115648

Adjacent sequences: A063732 A063733 A063734 this_sequence A063736 A063737 A063738

KEYWORD

nonn

AUTHOR

Jason Earls (zevi_35711(AT)yahoo.com), Aug 13 2001

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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