A086540 Numbers n such that n and n+1 both are members of A074997; i.e., on the one hand n-1 and n+1 have the same prime signature, on the other hand n and n+2 have the same prime signature.

18, 55, 248, 340, 348, 722, 850, 949, 1061, 1148, 1204, 1205, 1241, 1277, 1314, 1315, 1667, 1672, 2148, 2716, 2948, 2949, 3258, 3581, 3650, 3651, 4044, 4265, 4627, 4842, 5092, 5093, 5451, 5741, 5765, 6244, 6355, 6356, 6565, 6640, 6851, 6963, 7362, 7404

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Prog

(PARI) isok1(n) = vecsort(factor(n-1)[, 2]) == vecsort(factor(n+1)[, 2]);
isok(n) = isok1(n) && isok1(n+1); \\ Michel Marcus, Jul 28 2015

Crossrefs

Cf. A074997.

Sequence in context: A088593 A033571 A041632 * A041634 A044975 A251252

Adjacent sequences: A086537 A086538 A086539 * A086541 A086542 A086543

Keyword

nonn

Author

Amarnath Murthy, Aug 22 2003

Extensions

More terms from David Wasserman, Mar 21 2005

Status

approved