A231623 Smallest starting deficient number for n consecutive deficient numbers in arithmetic progression.

1, 1, 1, 2987, 801339, 221355125, 221355125

Offset: 3

Author

Shyam Sunder Gupta, Nov 11 2013

Keywords

• nonn
• hard
• more

Comments

The next term is a(10) > 10^9. The common difference for first 3 terms is 1 and for next 4 terms is 2.

Examples

			First and smallest occurrence of n, n >= 3, consecutive deficient numbers in arithmetic progression:
a(3) = 1: (1, 2, 3);
a(4) = 1: (1, 2, 3, 4);
a(5) = 1: (1, 2, 3, 4, 5);
a(6) = 2987: (2987, 2989, 2991, 2993, 2995, 2997);
a(7) = 801339: (801339, 801341, 801343, 801345, 801347, 801349, 801351);
a(8) = 221355125: (221355125, 221355127, 221355129, 221355131, 221355133, 221355135, 221355137, 221355139);
a(9) = 221355125: (221355125, 221355127, 221355129, 221355131, 221355133, 221355135, 221355137, 221355139, 221355141);
		

Crossrefs

Cf. A005100, A228433.