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

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Happy Number.

Example

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

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 *)

Crossrefs

Cf. A007770, A035502, A055629, A072494.

Sequence in context: A253752 A252317 A250026 * A234477 A286181 A045277

Adjacent sequences: A194349 A194350 A194351 * A194353 A194354 A194355

Keyword

nonn,base

Author

Martin Renner, Aug 22 2011

Status

approved