A318929 Intersection of A300216 and A306146.

1, 14, 22, 28, 44, 46, 56, 88, 92, 94, 112, 118, 166, 176, 184, 188, 214, 224, 236, 332, 334, 352, 358, 368, 376, 428, 448, 454, 472, 526, 664, 668, 694, 704, 716, 718, 736, 752, 766, 856, 896, 908, 934, 944, 958, 1006, 1052, 1126, 1174, 1328, 1336, 1388, 1408, 1432, 1436, 1438, 1472

Offset

1,2

Comments

Except for a(1) every element is either twice a prime or twice a previous element.

Primes obtained when a term is divided by 2 are of the form 4k + 3, k > 0.

Links

Table of n, a(n) for n=1..57.

Maple

isA318929 := proc(n)
    simplify(isA300216(n) and isA306146(n)) # reuses code of the other seqs.
end proc:
for n from 1 to 1500 do
    if isA318929(n) then
        printf("%d, ", n) ;
    end if;
end do: # R. J. Mathar, Feb 14 2019

Prog

(PARI)
is300216(k) = vecsort(factor(k)[, 2]) == vecsort(factor(eulerphi(k))[, 2]);
a023900(n) = sumdivmult(n, d, d*moebius(d));
is306146(n) = sdm = a023900(n); if(sdm < 0, return(0), sdmphi = a023900(eulerphi(n)); eulerphi(sdm) == sdmphi);
isok(n) = is300216(n) && is306146(n); \\ Michel Marcus, Sep 13 2018

Crossrefs

Cf. A300216, A306146.

Sequence in context: A354811 A092112 A306146 * A187776 A048196 A305084

Adjacent sequences: A318926 A318927 A318928 * A318930 A318931 A318932

Keyword

nonn

Author

Torlach Rush, Sep 11 2018

Extensions

More terms from Michel Marcus, Sep 15 2018

Status

approved