A176034 -id:A176034 - cp's OEIS frontend

A176036 Absolute values of A176035(n)-A176034(n).

1, 5, 3, 5, 1, 3, 9, 5, 7, 9, 9, 7, 7, 11, 3, 1, 3, 11, 15, 7, 3, 9, 17, 11, 9, 7, 1, 5, 7, 9, 9, 1, 9, 15, 17, 21, 19, 7, 1, 3, 17, 19, 21, 23, 21, 3, 3, 5, 9, 19, 11, 9, 1, 5, 9, 23, 19, 17, 15, 11, 9, 3, 5, 7, 9, 13, 15, 17, 21, 29, 11, 7, 13, 17, 25, 27, 27, 21, 15, 11, 3, 11, 29, 31, 23, 17

Offset: 1

Vladimir Joseph Stephan Orlovsky, Apr 06 2010

nonn

3-2=1, 6-1=5, 5-2=3, 6-1=5, 5-4=1,..

Cf. A006881, A056892, A106044, A176032, A176033, A176034, A176035

f1[n_]:=Floor[Sqrt[n]];f2[n_]:=Last/@FactorInteger[n]=={1,1};lst={};Do[If[f2[n],AppendTo[lst,Abs[(n-f1[n]^2)-((f1[n]+1)^2-n)]]],{n,0,5!}];lst

A176035 Difference between product of two distinct primes and previous perfect square.

Original entry on oeis.org

2, 1, 5, 6, 5, 6, 1, 8, 9, 10, 2, 3, 10, 2, 6, 8, 9, 13, 1, 5, 10, 13, 1, 4, 5, 6, 10, 12, 13, 14, 6, 11, 15, 18, 19, 1, 2, 8, 12, 13, 20, 21, 22, 1, 2, 11, 14, 15, 17, 22, 8, 9, 14, 16, 18, 25, 5, 6, 7, 9, 10, 13, 17, 18, 19, 21, 22, 23, 25, 1, 10, 12, 22, 24, 28, 29, 3, 6, 9, 11, 18, 22, 31

Offset: 1

Vladimir Joseph Stephan Orlovsky, Apr 06 2010

6-4=2, 10-9=1, 14-9=5, 15-9=6, 21-16=5,..

G. C. Greubel, Table of n, a(n) for n = 1..5000

Cf. A006881, A056892, A106044, A176032, A176033, A176034

A006881:= [n: n in [1..1000] | EulerPhi(n) + DivisorSigma(1, n) eq 2*(n+1)];
[A006881[n] - Floor(Sqrt(A006881[n]))^2: n in [1..100]]; // G. C. Greubel, Oct 26 2022

A006881=Sort@Flatten@Table[Prime[m]*Prime[n], {n, 2, 150}, {m, n-1}];
Table[A006881[[n]]-Floor[Sqrt[A006881[[n]]]]^2, {n, 100}] (* Vladimir Joseph Stephan Orlovsky, Jun 02 2011 *)

A006881=[n for n in (1..750) if euler_phi(n) + sigma(n,1) == 2*n+2]
[A006881[n] - isqrt(A006881[n])^2 for n in range(101)] # G. C. Greubel, Oct 26 2022

a(n) = A053186(A006881(n)). - R. J. Mathar, Aug 25 2025

cp's OEIS Frontend

A176036 Absolute values of A176035(n)-A176034(n).

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A176035 Difference between product of two distinct primes and previous perfect square.

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