A080064 -id:A080064 - cp's OEIS frontend

A080065 Numbers n such that n == 3 modulo (spf(n)+1), where spf(m) is the smallest prime dividing m (A020639).

3, 15, 27, 39, 51, 63, 75, 87, 91, 99, 111, 123, 135, 147, 159, 171, 183, 195, 203, 207, 219, 231, 243, 255, 259, 267, 279, 291, 303, 315, 327, 339, 351, 363, 371, 375, 387, 399, 411, 423, 427, 435, 447, 459, 471, 483, 495, 507, 519, 531, 539, 543, 555, 567

Offset: 1

Reinhard Zumkeller, Jan 24 2003

nonn

A080063(m) = 3 iff m = a(k) for some k.

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A080064.

Select[Range[600],Mod[#,FactorInteger[#][[1,1]]+1]==3&] (* Harvey P. Dale, Aug 15 2013 *)

A080063 a(n) = n mod (spf(n)+1), where spf(n) is the smallest prime dividing n (A020639).

Original entry on oeis.org

1, 2, 3, 1, 5, 0, 7, 2, 1, 1, 11, 0, 13, 2, 3, 1, 17, 0, 19, 2, 1, 1, 23, 0, 1, 2, 3, 1, 29, 0, 31, 2, 1, 1, 5, 0, 37, 2, 3, 1, 41, 0, 43, 2, 1, 1, 47, 0, 1, 2, 3, 1, 53, 0, 1, 2, 1, 1, 59, 0, 61, 2, 3, 1, 5, 0, 67, 2, 1, 1, 71, 0, 73, 2, 3, 1, 5, 0, 79, 2, 1, 1, 83, 0, 1, 2, 3, 1, 89, 0, 3, 2, 1, 1, 5, 0

Offset: 1

Reinhard Zumkeller, Jan 24 2003

a(n) = 0 iff n mod 6 = 0 (A008588);
a(n) = 2 iff n mod 6 = 2 (A016933);
for n>1: a(n)=n iff n is prime (A000040, A008578).

Cf. A080064, A080065, A010872, A010873, A010875, A010877, A010881.

cp's OEIS Frontend

A080065 Numbers n such that n == 3 modulo (spf(n)+1), where spf(m) is the smallest prime dividing m (A020639).

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