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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
-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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 17 07:35 EDT 2021. Contains 347478 sequences. (Running on oeis4.)