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A074384 Solutions to Mod[sigma[x],6]=5. 6
2401, 9604, 21609, 28561, 38416, 60025, 86436, 114244, 130321, 153664, 194481, 240100, 257049, 290521, 345744, 456976, 521284, 540225, 614656, 693889, 714025, 777924, 923521, 960400, 1028196, 1162084, 1172889, 1270129, 1382976, 1500625 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

4th powers of primes of the form 6k+1 are here because sigma[p^4]=p^4+p^3+p^2+p+1 congruent 1+1+1+1+1=5 mod 6. There are also other solutions.

MATHEMATICA

Do[s=Mod[DivisorSigma[1, n], 6]; If[s==5, Print[n]], {n, 1, 1000000}]

CROSSREFS

Cf. A000203, A072862, A072461, A072462.

Sequence in context: A186487 A043396 A103125 * A016924 A016984 A017152

Adjacent sequences:  A074381 A074382 A074383 * A074385 A074386 A074387

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Aug 22 2002

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Last modified February 16 17:48 EST 2012. Contains 205939 sequences.