A194352 First of quadruples of consecutive happy numbers.

7839, 8739, 11248, 12148, 21148, 44488, 44489, 44939, 49439, 70839, 78039, 80739, 87039, 94439, 101248, 102148, 110248, 112048, 120148, 121048, 201148, 210148, 211048, 222688, 222689, 226288, 226289, 236839, 238639, 258598, 258599, 262288, 262289, 263839

Offset: 1

Author

Martin Renner, Aug 22 2011

Keywords

• nonn
• base

Examples

			7839, 7840, 7841, 7842 are the first of four consecutive integers each of which is a happy number, hence a(1) = 7839.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Happy Number.

Crossrefs

Cf. A007770, A035502, A055629, A072494.

Programs

Mathematica

f[n_] := Total[IntegerDigits[n]^2]; t = Select[Range[300000], NestWhile[f, #, UnsameQ, All] == 1 &]; t[[Select[Range[Length[t] - 3],  t[[#]] == t[[# + 1]] - 1 == t[[# + 2]] - 2 == t[[# + 3]] - 3 &]]] (* T. D. Noe, Aug 22 2011 *)