A071167 A062700(n)-A023194(n). Negative values of A071166(m)=m-A006530[A000203[m]] differences. In these cases m is square number from A023194.

-1, -3, -4, -15, -6, -63, -18, -364, -42, -400, -60, -4095, -72, -90, -102, -3906, -132, -168, -2380, -174, -65535, -5220, -294, -384, -262143, -12720, -678, -702, -265720, -744, -762, -774, -828, -840, -25260, -858, -912, -1092, -1098, -1164, -1182, -1194, -1218, -1374, -1428, -1488, -1560

Offset

1,2

Links

Table of n, a(n) for n=1..47.

Formula

Values of m-A006530[A000203(m)] differences, when m < A006530[A000203(m)].

Example

m=29929=173, sigma[29929]=1+173+29929=30103 and 29929-30103=-174, the 20th term here.

Mathematica

ma[x_] := Part[Reverse[Flatten[FactorInteger[x]]], 2] Do[s=n-ma[DivisorSigma[1, n]]; If[Equal[Sign[s], -1], Print[s]], {n, 2, 10000000}]

Prog

(PARI) for(n=1, 1e3, if(isprime(s=sigma(n^2)), print1(n^2-s", "))) \\ Charles R Greathouse IV, Feb 19 2013

Crossrefs

Cf. A000203, A006530, A062700, A023194, A071166.

Sequence in context: A327275 A343939 A157351 * A194924 A205489 A343935

Adjacent sequences: A071164 A071165 A071166 * A071168 A071169 A071170

Keyword

sign

Author

Labos Elemer, May 15 2002

Status

approved