A228556 -id:A228556 - cp's OEIS frontend

A228541 Numbers having at least one prime factor of the form 30*k + 1.

31, 61, 62, 93, 122, 124, 151, 155, 181, 183, 186, 211, 217, 241, 244, 248, 271, 279, 302, 305, 310, 331, 341, 362, 366, 372, 403, 421, 422, 427, 434, 453, 465, 482, 488, 496, 527, 541, 542, 543, 549, 558, 571, 589, 601, 604, 610, 620, 631, 633, 651, 661, 662

Offset: 1

Arkadiusz Wesolowski, Aug 25 2013

Together with 2, supersequence of A228556.

Conjecture: Numbers m such that abs(Sum_{k=1..m} [k|m]*A008683(k)*(-1)^(k/15)) = 0. - Mats Granvik, Jul 06 2024

			183 = 3*61 is in the sequence because 30*2 + 1 is prime.
211 is in the sequence because it is prime and 211 = 30*7 + 1.

Supersequence of A132230. Cf. A228556.

for(n=31, 662, if(setsearch(Set(factor(n)[, 1]%30), 1)==1, print1(n, ", ")));

A228542 Numbers that are sums of two coprime positive fifth powers.

Original entry on oeis.org

2, 33, 244, 275, 1025, 1267, 3126, 3157, 3368, 4149, 7777, 10901, 16808, 16839, 17050, 17831, 19932, 24583, 32769, 33011, 35893, 49575, 59050, 59081, 60073, 62174, 75856, 91817, 100001, 100243, 116807, 159049, 161052, 161083, 161294, 162075, 164176, 168827

Offset: 1

Arkadiusz Wesolowski, Aug 25 2013

nonn

			244 is in the sequence since 1^5 + 3^5 = 244 and (1, 3) = 1.

Supersequence of A228556. Cf. A002561, A055014.

lst:=[]; for m in [2..168827] do f:=func; if f(m)[1] gt 0 and GCD(f(m)[1], f(m)[2]) eq 1 then Append(~lst, m); end if; end for; lst; // Arkadiusz Wesolowski, Dec 19 2020

cp's OEIS Frontend

A228541 Numbers having at least one prime factor of the form 30*k + 1.

Views

Author

Keywords

Comments

Examples

Crossrefs

Programs

PARI