A325377 - OEIS

A325377

a(n) = A001065(A228058(n)), where A001065(n) gives the sum of proper divisors of n.

33, 65, 81, 97, 129, 109, 161, 177, 321, 133, 225, 257, 193, 161, 305, 205, 369, 193, 253, 401, 417, 253, 449, 465, 277, 641, 561, 349, 609, 801, 641, 289, 397, 397, 705, 289, 737, 785, 801, 481, 353, 469, 385, 337, 929, 945, 977, 2241, 565, 1041, 1281, 1089, 613, 1121, 637, 1137, 481, 1185, 673, 685, 1265, 709, 1281, 421, 2717, 545, 1601

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OFFSET

1,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..25000

FORMULA

a(n) = A001065(A228058(n)).

a(n) > A325320(n) for all n.

PROG

(PARI)

up_to = 25000;

isA228058(n) = if(!(n%2)||(omega(n)<2), 0, my(f=factor(n), y=0); for(i=1, #f~, if(1==(f[i, 2]%4), if((1==y)||(1!=(f[i, 1]%4)), return(0), y=1), if(f[i, 2]%2, return(0)))); (y));

A228058list(up_to) = { my(v=vector(up_to), k=0, n=0); while(k<up_to, n++; if(isA228058(n), k++; v[k] = n)); (v); };

v228058 = A228058list(up_to);

A228058(n) = v228058[n];

A001065(n) = (sigma(n)-n);

A325377(n) = A001065(A228058(n));

CROSSREFS

Cf. A001065, A228058, A325320, A325380.

Sequence in context: A062059 A285317 A198592 * A061560 A118618 A163411

Adjacent sequences: A325374 A325375 A325376 * A325378 A325379 A325380

KEYWORD

nonn

AUTHOR

Antti Karttunen, Apr 22 2019

STATUS

approved